Phyton-International Journal of Experimental Botany

Physiological and Biochemical Role of Pathogen-related Protein 10 (Pr10) Under Abiotic and Biotic Stresses in Plants

Anshu Rastogi — 2020-05-21

Members of the Pathogenesis Related (PR) 10 protein family have been identified in a variety of plant species and a wide range of functions ranging from defense to growth and development have been attributed to them. PR10 proteins are induced by pathogen attack in a wide variety of plants, as well as in response to abiotic stresses. Some PR10 members have been reported to possess ribonuclease (RNase) activity, while others have been reported to interact with phytohormones, suggesting a role in hormone-mediated signaling, particularly in response to biotic and abiotic stresses. Furthermore, the expression of PR10 cDNA in a variety of plants afforded protection against various phytopathogenic fungi, bacteria, and viruses. One possible mechanism for such resistance to pathogens could be due to the RNase activity of PR10 proteins, likely through the degradation of RNA of the invading pathogens. The resistance mechanism may include activation of defense signaling pathways through possible interacting proteins involved in mediating responses to pathogens. In addition to enhanced disease resistance in transgenic plants expressing PR10, there are reports that the constitutive expression of the PR10 cDNA also enhances tolerance to abiotic stresses. Moreover, a number of morphological changes have been shown to accompany the enhanced abiotic stress tolerance. The precise mechanism(s) underlying PR10-mediated biotic and abiotic stress tolerance is currently unknown as are the specific roles for this group of proteins during normal plant growth and development. The updated and available information on this interesting group of proteins is reviewed in this article.

From markers to genome based breeding in horticultural crops: an overview

Riaz Ahmad — 2020-05-21

Molecular markers, genome sequencing and genome editing are considered as efficient and versatile tools to accomplish demands of plant breeders for crop improvement programs. Morphological and biochemical markers have not been extensively used as these are greatly influenced by environmental factors. Different molecular markers and sequencing techniques are routinely used in evaluation of genetic diversity and evolutionary relationship, accurate classification or taxonomy, characterization of germplasm, identification of hybrids and phylogenetic studies. These molecular markers are well established and have successfully been used for genetic analysis of different plants during last two decades. Recently, advanced techniques of molecular markers have been developed form earlier and basic techniques or their combination. This advanced class tends to merge valuable properties of many basic systems. New class of markers also includes little modifications in basic methods to enhance the sensitivity and resolution for evaluation of genetic gap. Current review provides detailed description of different markers, genome sequencing and genome editing that were further utilized for different genetic analysis of horticultural crops.

Keywords: Genetic analysis; Genome sequencing; Genome editing; Molecular markers; Plant breeders.

MULTIFACETED STRATEGIES USED BY ROOT-KNOT NEMATODES TO PARASITIZE PLANTS- A REVIEW

Adnan Shakeel — 2020-05-21

Root-knot nematodes being omnipresent in agricultural and horticultural soils are tallied among the most important economic pathogens around the world. For successful parasitism, these nematodes use various strategies to control and manipulate the host plant’s cell machinery. These strategies include the molecular mimicry of some host genes by some nematode secreted effectors, secretion of cell wall digesting enzymes and other effectors that are responsible for the suppression of defence by the host plant. All these secretions which are released through the stylet, contribute to the formation of specialized feeding sites or giant cells. The effector proteins interfere with the normal physiology, cytology and biochemistry of the host plant. This review brings novel insights by summarizing some novel effectors that have been discovered recently like MiIDL1, MiISE6, Mg16820, etc. It also discusses some novel mechanisms through which these effectors target different pathways of host plant and thus facilitate nematode parasitism.

ACC Deaminase Producing Bacteria and Biochar: Key mitigators of drought stress in plants

Muhammad Zafar-ul-Hye — 2020-05-21

Most of the cereal crops are widely cultivated to fulfil the humans food requirements. Under changing climate scenario, the intensity of drought stress is continuously increasing that is adversely affecting the growth and yield of cereal crops. Although these cereals can tolerate moderate drought to some extent, but most they are susceptible to severe drought stress. Therefore, for optimization of cereal crops yield, it is very important to understand physiological and biochemical attributes especially hormonal changes in plants which are associated with limited availability of water. Higher biosynthesis of ethylene under drought stress has been reported earlier. Many scientists observed that inoculation of ACC deaminase producing PGPR is an efficacious tool to overcome this problem. These PGPR secrete ACC deaminase which cleavage the ACC into the compounds, other than ethylene. Furthermore, secretion of growth hormones also play imperative role in enhancing the growth of the cereals under limited availability of water. In addition, the use of biochar has also been recognized as another effective amendment to grant resistance against drought. Biochar application improves the soil physiochemical attributes i.e., porosity, nutrients retention and water holding capacity which decrease the loss of water and increase its bioavailability. In recent era, the idea of combined use of ACC deaminase producing PGPR and biochar is becoming popular which might be more efficient to use water under drought stress. The aim of this novel idea is to grant maximum resistance to crops against drought stress. Some scientists have observed significant improvement in yield of cereal crops by combined use of ACC deaminase producing PGPR and biochar. However, more research is suggested for deep understanding of complex synergistic mechanism of ACC deaminase activity in combination with biochar.

Genome-wide identification of the F-box gene family and expression analysis under drought and salt stress in barley

Dawei Xue — 2020-05-21

The F-box protein-encoding gene family plays an essential role in plant stress resistance. In present study, 126 non-redundant F-box genes were identified. The corresponding proteins contained 165–887 amino acid residues and all were amphiphilic, except 5 proteins. Phylogenetic analysis was used to classify the F-box genes into 9 subfamilies (A–I). A structure-based sequence alignment demonstrated that F-box proteins were highly conserved with a total of 10 conserved motifs. In total, 124 F-box genes were unevenly distributed on 7 chromosomes; another 2 genes have not been anchored yet. The gene structure analysis revealed high variability in the number of exons and introns in F-box genes. Of the 12 detected F-box genes, 8 and 10 were upregulated after drought and salt stress treatments, respectively, using quantitative real-time polymerase chain reaction (qRT-PCR). This study is the first systematic analysis conducted on the F-box gene family in barley, which is of great importance for clarifying this family’s bioinformatic characteristics and elucidating its function in barley stress resistance. These results will serve as a theoretical reference for subsequent research on molecular regulation mechanisms, genetic breeding, and improvement.

Genome-Wide Identiﬁcation and Expression Proﬁling of Brassica napus Invertase Genes Suggest Roles in Silique Development and the Response to Sclerotinia sclerotiorum

Jingsen Liu — 2020-05-21

Invertase (INV) is one of the key enzymes in plant sucrose metabolism. It irreversibly catalyzes the hydrolysis of sucrose to glucose and fructose, and thus plays an important role in plant growth, development, and in responses to biotic and abiotic stress. In this study, we identiﬁed 27 members of the BnINV family in Brassica napus. We constructed a phylogenetic tree of the family and predicted the gene structures, conserved motifs, promoter cis-acting elements, physicochemical protein properties, and chromosomal distributions of the BnINVs. We also analyzed the expression of the BnINVs in different tissues and developmental stages in the B. napus cultivar Zhongshuang 11 using qRT-PCR. In addition, we analyzed RNA-sequencing data to explore the expression patterns of the BnINVs in four different harvest index cultivars and inoculated with the pathogenic fungus Sclerotinia sclerotiorum. We used a weighted coexpression network analysis to explore the BnINV regulatory networks. Finally, we selected some BnINV genes and explored their expression patterns in long (Zhongshuang 4) and short (Ningyou 12) silique rapeseed cultivars. Our results showed that the BnINVs might play important roles in the growth and development of rapeseed siliques and the defense response against pathogens.

Effects of Different Color Lights from LED on the Growth, Development and Reproduction of Arabidopsis thaliana

Tengyue Zou — 2020-05-21

Light is the major source of energy for plants and as such has a profound effect on plant growth and development. Red and blue lights have been considered to best drive photosynthetic metabolism and are beneficial for plant growth and development, and green light was seen as a signal to slow down or stop. In this study, Arabidopsis thaliana (A. thaliana) was used to investigate the effects of red, blue and green lights on the growth and development of plants from seed germination to seeding. Results demonstrated that red light showed a promotion effect but blue light a prohibition one in most stages except for the flowering time in which the effect of each light was just reversed. When mixed with red or blue light, green light generally at least partially cancelled out the effects caused by each of them. Results also showed that the same number of photons the plant received could cause different effects and choosing the right combination of different color of lights is essential in both promoting the growth and development of plants and reducing the energy consumption of lighting in plant factory.

Effects of Different Selenium Application Methods on Wheat (Triticum aestivum L.) Biofortification and Nutritional Quality

Yong Liang — 2020-05-21

Abstract: Mineral nutrient malnutrition, especially deﬁciency in selenium (Se), affects the health of approximately 1 billion people worldwide. Wheat, a staple food crop, plays an important role in producing Se-enriched foodstuﬀs to increase the Se intake of humans. This study aimed to evaluate the effects of different Se application methods on grain yield and nutritional quality, grain Se absorption and accumulation, as well as 14 other trace elements concentrations in wheat grains. A sand culture experiment was conducted via a completely randomized 2 x 2 x 1 factorial scheme (three Se levels x two methods of Se application, foliar or soil x one Se sources, selenite), with two wheat cultivars (Guizi No.1, Chinese Spring). The results showed that both foliar Se and soil Se application methods had effects on wheat pollination. Foliar Se application resulted in early flowering of wheat, while soil Se application caused early flowering of wheat at low Se levels (5 mg kg^-1) and delayed wheat flowering at high selenium levels (10 mg kg^-1), respectively. For trace elements, human essential trace elements (Fe, Zn, Mn, Cu, Cr, Mo, Co and Ni) concentrations in wheat grains were dependent of Se application methods and wheat cultivars. However, toxic trace elements (Cd, Pb, Hg, As, Li and Al) concentrations can be decreased by both methods, indicating a possible antagonistic effect. Moreover, both methods increased Se concentrations, and improved grain yield and nutritional quality, while the foliar application was better than soil. Accordingly, this study provided useful information concerning nutritional biofortiﬁcation of wheat, indicating that it is feasible to apply Se to conduct Se biofortification, inhibit the heavy metal elements concentrations and improve yield and quality in crops, which caused human health beneﬁts.
Keywords: Selenium; grain yield and nutritional quality; trace elements; wheat; biofortiﬁcation

Biochar Application Enhanced Post-Heading Radiation Use Efficiency in Field-Grown Rice (Oryza sativa L.)

Min Huang — 2020-05-21

Biochar may be a beneficial soil amendment for crop production, and it is well-documented that biochar application can improve nitrogen (N) uptake and/or utilization in rice (Oryza sativa L.). However, limited information is available on the effects of altered plant N status induced by applying biochar on physiological aspects in rice. In this study, field experiments were conducted in 2015 and 2016 to test the hypothesis that biochar application may enhance radiation use efficiency (RUE) in rice by improving the plant N status. The results showed that biochar application (20 t ha^–1) had no significant or consistent effects on pre-heading N uptake (NUpre), leaf area index (LAI) and specific leaf weight (SLW) at heading, ratios of LAI/NUpre and SLW/Nupre, and pre-heading RUE. However, biochar application significantly increased post-heading N uptake (NUpost), ratios of NUpost/LAI and NUpost/SLW, and post-heading RUE. These results indicate that biochar application can improve the plant N status and RUE in field-grown rice during the post-heading period, supporting our hypothesis.

ASSESSMENT OF CONTRIBUTION OF FOLIAR TRICHOMES TOWARDS ALLELOPATHY

Khalid Rehman HAKEEM — 2020-05-21

Plant trichomes vary in their structure, extents and cellular composition. Some forms, commonly known as glandular trichomes, contain a bulk of specific (secondary) metabolites of diverse nature. Trichomes are connected with various adaptive processes which include protection against herbivores and pathogens as well. Since trichomes jut from the epidermis and can frequently be smoothly isolated from it and gathered, the mRNAs, proteins and other molecules that they contain are remarkably open to investigation. This property marks them exceptional trial frameworks for distinguishing proof of the enzymes and pathways in charge of the synthesis of the particular metabolites produced by these structures and in some cases somewhere else in the plant. Our study investigates the allelopathic contribution of structures present on the leaf surface of Nicotiana plumbaginifolia Viv. against seedling growth of Cicer arietinum L. The infusion obtained after dipping Nicotiana leaves in Dichloromethane (DCM) for 10 s was the most phytotoxic among all the infusions. The observed inhibition in Cicer growth was not only dependent on type of infusion but also the concentration. Glandular trichomes were most dehydrated at 10 s in DCM, suggesting their role for the observed allelopathy. Such study on the biochemistry of trichomes and their phytotoxicity may develop them highly valuable objects for plant metabolic engineering.

Multi-strain inoculation with PGPR producing ACC deaminase is more effective than single-strain inoculation to improve wheat (Triticum aestivum) growth and yield

Muhammad Zafar-ul-Hye — 2020-05-21

Rhizosphere bacteria that colonize plant roots and confer beneficial effects are referred as plant growth promoting rhizobacteria (PGPR). Among all PGPR, some rhizobacteria have an ability to produce ACC deaminase enzyme. This enzyme catalyzes stress ACC into a-ketobutyrate and ammonia istead of letting it to be converted to ethylene. Ethylene level rises in plants under stress conditions i.e., drought, salinity, poor soil fertility etc. As poor soil fertility, is a big hurdle to achieve the optimum yield of crops, inoculation of ACC deaminase PGPR can overcome this problem to some extent. The aim of the current study was to examine the influence of multi-strain and single-strain inoculation of different ACC deaminase producing PGPR on wheat growth and yield. There were three PGPR strains, Enterobacter cloacae, Serratia ficaria and Burkholderia phytofirmans which were used as consortia and single-strain inoculations. The results showed that inoculation of E. cloacae + S. ficaria + B. phytofirmans significantly increased plant height (63%), spike length (61%), number of spikelets spike-1 (61%), number of grains spike^-1 (131%), 1000 grains weight (33%), grains yield (71%), straw yield (71%) and biological yield (68%) of wheat as compared to control. A significant improvement in N (37 and 200%), P (46 and 166%) and K (39 and 61%) of seeds and shoot respectively, validated the efficacious and more effective role of multi-strain (E. cloacae + S. ficaria + B. phytofirmans) inoculation over control. It is obviously concluded that multi-strain ACC deaminase producing PGPR inoculation is a better approach as compared to single-strain inoculation for the improvement in growth and yield of wheat.

Vegetative Compatibility and Virulence Diversity of Verticillium dahliae from Okra (Abelmoschus esculentus) Plantations in Turkey and Evaluation of Okra Genotypes for Resistance to Verticillium dahliae

Fatih Mehmet Tok — 2020-05-21

Forty-four V. dahliae isolates were collected from symptomatic vascular tissues of okra plants each from a different field in eight provinces located in the eastern Mediterranean and western Anatolia regions of Turkey during 2006-2009. Nitrate-nonutilizing (nit) mutants of V. dahliae from okra were used to determine heterokaryosis and genetic relatedness among isolates. All isolates from okra plants were grouped into two vegetative compatibility groups (VCGs) (1 and 2) and three subgroups as 1A (13.6%, 6/44), 2A (20.5%, 9/44) and 2B (65.9%, 29/44) according to international criteria. Pathogenicity tests were performed on a susceptible local okra (A. esculentus) landrace in greenhouse conditions. All isolates from VCG1A and VCG2B induced defoliation (D) and partial defoliation (PD) symptoms, respectively. Other isolates from VCG2A gave rise to typical leaf chlorosis symptoms without defoliation. These data showed that the virulence level of V. dahliae isolates from okra was related to their VCG belongings. Eighteen okra genotypes (landraces) from diverse geographical origins were screened for resistance to VCG2B and VCG1A of V. dahliae. The results indicated that all genotypes were more susceptible to highly virulent VCG1A-D pathotype than to less virulent VCG2B-PD pathotype of V. dahliae. Significant differences were observed among the genotypes; however, none of them exhibited a level of resistance. Only Çorum, Hatay Has and Şanlıurfa genotypes displayed the lowest level of susceptibility or little tolerance to both D and PD pathotypes. VCG2B of PD was prevailing in the surveyed areas and VCG1A of D was the most virulent of the VCGs identified.

Reference Gene Selection for Quantitative Real-time PCR Analyses of Acer palmatum under Abiotic Stress

Lu Zhu — 2020-05-21

Abstract. Quantitative real-time reverse transcriptase PCR (qRT-PCR) technology has been extensively used to estimate gene expression levels, and the selection of appropriate reference genes for qRT-PCR analysis is critically important for obtaining authentic normalized data. Acer palmatum is an important colorful leaf ornamental tree species, and reference genes suitable for normalization of the qRT-PCR data obtained from this species have not been investigated. In this study, the expression stability of ten candidate reference genes, namely, Actin3, Actin6, Actin9, EF1α, PP2A, SAMDC, TIP41, TUBα, TUBβ and UBQ10, in two distinct tissues (leaves and roots) of A. palmatum under four different abiotic (cold, heat, salt and drought) stress conditions were investigated and assessed using three statistical methods (GeNorm, NormFinder and BestKeeper). The combinations of reference genes that showed stability in the different stressed samples were different. Specifically, Actin3, Actin6, Actin9 and UBQ10 were the most stable reference genes in all the samples, and Actin3 and Actin6 were stably expressed in cold-stressed leaves and roots. Actin3, Actin6 and UBQ10 were identified as an appropriate combination of reference genes for the analysis of heat-stressed leaves and roots, whereas the combination of Actin9, UBQ10 and Actin6 was deemed the most suitable for the analysis of salt-stressed leaves and roots. Similarly, Actin6 and UBQ10 exhibited stable expression in drought-stressed leaves and roots. Furthermore, the expression levels of ApCBF were estimated to determine the reliability of the reference genes assessed in this study. This study revealed stable reference genes in A. palmatum that might be used for the normalization of qRT-PCR data obtained under various abiotic stresses.

Cadmium-induced the Structure Change of Pigment Gland and the Decrease of Gossypol Content in Cottonseed Kernels

Ling Li — 2020-05-22

The risk of cotton production on arable land contaminated with heavy metals has increased in recent years. Although cotton shows stronger and widespread resistance to heavy metals such as cadmium (Cd) than other major crops. Here, a pot experiment was performed in order to study Cd-induced alterations in seed kernel gossypol content and pigment gland structure at maturity in two transgenic cotton cultivars (ZD-90 and SGK3) and an upland cotton standard genotype (TM-1). The results showed that Cd accumulation in cottonseed kernels increased with increase on Cd levels in the soil. The seed kernel Cd content in plants grown on Cd treated soils was 10-20 times more than the amount in their controls. There was significant difference on Cd accumulation in cottonseed kernels at 400 and 600 μM Cd level. It was higher in SGK3 and ZD-90 than that in TM-1. However, gossypol content in cottonseed kernels was lower in SGK3 or ZD-90 than that in TM-1. There was a negative correlation (r=0.550) between Cd accumulation and gossypol content in cottonseed kernels. The density of cottonseed kernels pigment gland decreased under Cd stress. It is consistent with the change of gossypol content, which decreased under Cd stress. The damage of ZD-90 and SGK3 was much less under Cd stress while TM-1 was the most severely and Cd sensitivity. Further studies are necessary to understand the cause of the decrease in gossypol content under Cd stress.

Internal Reference Gene Selection For Quantitative Real-Time RT-PCR Normalization In Potato

浩力马 — 2020-05-22

Quantitative real-time RT-PCR (qRT-PCR), which is widely used for investigating gene expression patterns, has many advantages such as high sensitivity, high fidelity, and high specificity. Selecting a satisfactory internal reference gene is crucial to precise result of gene expression in qRT-PCR experiments. In the present study, the transcriptomic data of two potato varieties were used to screen housekeeping genes with stable expression patterns. A total of 77 putative genes were chose which were highly and stably expressed. Then qRT-PCR experiments were performed to examine the expression levels of these 77 candidate reference genes in potato tissues including leaves, flowers, stolons, and tubers. The gene expression was represented by analyzing the Ct values at given threshold. Through geNorm and NormFinder program analyses, ten candidate genes with most stable expression patterns were got, including RPL19, RPS15, RPS9, EF1α, TrxP1, RPS28, NTF, CAM, AACM, and RPS28. Moreover, through comprehensive analyses of four statistical algorithms geNorm, NormFinder, BestKeeper and RefFinder, the results indicated that the most appropriate internal reference genes were RPL19 and EF1α. The obtained identifications of stable reference genes will contribute to subsequent qRT-PCR analysis of gene expression related to potato tissues.

Morpho-anatomy of the Echium plantagineum L. (Boraginaceae) diaspores in relation with water uptake and germination

María Laura Molinelli — 2020-05-22

Echium plantagineum (Boraginaceae) is native to the Mediterranean, it grows from the United States, Mexico, to Brazil, Chile, Uruguay and Argentina. The objectives of this research were: (i) to study the morpho-anatomy of the diaspores of E. plantagineum; (ii) to identify the pathway of water uptake; and (iii) to characterize the germination and the seedling. The morpho-anatomical studies were carried out analyzing semi-permanent and permanent slides of transverse and longitudinal sections of the fruits, the seeds and the seedlings. Histological, histochemical and conventional staining techniques were used for the analysis with stereoscopic, optical and scanning electron microscopy. The water pathway was determined with fast green staining, germination tests were performed and the seedlings were analyzed. The diaspores showed to be formed by the acrescent calyx with the fruit, compound by 4 rough tuberculate mericarps. Each indehiscent mericarp encloses an exalbuminous seed with a thin seed coat and a spatulate embryo with folded cotyledons. Water uptake took place through the protuberance in the abscission scar of the mericarp. Germination was epigeal, the cotyledons were photosynthetically active at the emergence, and a rudimentary developed gemmula was observed. Germination percentage was 66.5 %. The presence of macrosclereids with tannins in the pericarp, neither constitute a barrier for the water uptake nor represent an obstacle for germination.

Phytochemicals and antioxidant activities during fruit-ripening on Chamaedorea radicalis Mart.

Jorge Ariel Torres-Castillo — 2020-05-22

This work aims to determine the phytochemical characterization of the pericarp of Chamaedorea radicalis Mart. fruit as a non-timber product with potential to obtain phytochemicals with potential applications in medicine or in the industry. Determinations of total phenolic compounds, free radical scavenging activities and total flavonoid contents using spectrophotometric methods were done. Also, the identification of phytochemicals was done using UPLC-MS-MS in the four fruit ripeness stages. Total phenolic compound (TPC) content ranged from 7.24 to 12.53 mg gallic acid equivalents per gram of fresh weight (mg GAE/g FW). Total flavonoids (TF) contents ranged from 0.163 to 0.23 mg of quercetin equivalents per g FW (mg QE/g FW). Free radical scavenging activity against DPPH and ABTS radicals varied from 40.80 to 53.68 and from 22.29 to 37.76 mmol Trolox equivalents g FW (mmol TE/g FW), respectively. Antioxidant capacity determined by FRAP (ferric reducing antioxidant power) showed that S3 was the highest level with antioxidant power while S4 was the lowest withRed ripeness stage showed the lowest contents for all determinations. Mass spectrometry allowed detection of 26 compounds, including phenolics, alkaloids and saponins. Afzelin, Kaempferol 3-neohesperidoside and the four saponins identified were present in all ripeness stages. Phytochemicals and the spectrophotometric determinations showed that the pericarp of C. radicalis is potential source for applications in medicine; although, the presence and abundance of each phytochemical regarding each ripeness stage should be considered.

The Chloroplast Genome of Cerasus Campanulata Gives Insight Into Diverse Phylogenetics With Other Prunoideae Genomes

Yuhao Weng — 2020-05-22

Cerasus Campanulata is one of species which belongs to the Prunoideae focke, a subfamily of the flowering plant Rosaceae order. Here we use the complete chloroplast (cp) genome sequence of C. campanulata and make Sequence analysis to reveal the presence of 18 forward repeats, 20 palindrome repeats, 2 complement repeats, 4 reverse repeats and 93 simple sequence repeats (SSRs). A comparative study of C. campanulata and seven other Prunoideae focke species was carried out. Maximum parsimony (MP) and maximum likelihood (ML) phylogenetic analyses were performed in the little part of Rosaceae order to verify the Phylogenetic analyses which used Bayesian analysis and were performed based on 62 protein-coding genes from 57 species again. The complete cp genome can be used for plant phylogenetic and evolutionary studies and will provide insight into the degree of gene conservation. Moreover, the results strongly support the position of C. campanulata as a member of the Rosaceae order.