Genetic dissection of marker trait associations for grain micro-nutrients and thousand grain weight under heat and drought stress conditions in wheat

IntroductionWheat is grown and consumed worldwide, making it an important staple food crop for both its calorific and nutritional content. In places where wheat is used as a staple food, suboptimal micronutrient content levels, especially of grain iron (Fe) and zinc (Zn), can lead to malnutrition. Grain nutrient content is influenced by abiotic stresses, such as drought and heat stress. The best method for addressing micronutrient deficiencies is the biofortification of food crops. The prerequisites for marker-assisted varietal development are the identification of the genomic region responsible for high grain iron and zinc contents and an understanding of their genetics.MethodsA total of 193 diverse wheat genotypes were evaluated under drought and heat stress conditions across the years at the Indian Agricultural Research Institute (IARI), New Delhi, under timely sown irrigated (IR), restricted irrigated (RI) and late sown (LS) conditions. Grain iron content (GFeC) and grain zinc content (GZnC) were estimated from both the control and treatment groups. Genotyping of all the lines under study was carried out with the single nucleotide polymorphisms (SNPs) from Breeder’s 35K Axiom Array.Result and DiscussionThree subgroups were observed in the association panel based on both principal component analysis (PCA) and dendrogram analysis. A large whole-genome linkage disequilibrium (LD) block size of 3.49 Mb was observed. A genome-wide association study identified 16 unique stringent marker trait associations for GFeC, GZnC, and 1000-grain weight (TGW). In silico analysis demonstrated the presence of 28 potential candidate genes in the flanking region of 16 linked SNPs, such as synaptotagmin-like mitochondrial-lipid-binding domain, HAUS augmin-like complex, di-copper center-containing domain, protein kinase, chaperonin Cpn60, zinc finger, NUDIX hydrolase, etc. Expression levels of these genes in vegetative tissues and grain were also found. Utilization of identified markers in marker-assisted breeding may lead to the rapid development of biofortified wheat genotypes to combat malnutrition

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Not AvailableTerminal heat stress (HS) has adverse efect on the quantity and quality of wheat grains, as evident from the reduction in the yield. Plant has inherited tolerance mechanism to protect itself from the environmental stresses by modulating the expression and activity of stress associated genes (SAGs)/proteins (SAPs) which protect the plant from the damage caused by HS. Heat shock transcription factor (HSF) regulates the expression of SAGs in plant under HS. Bioinformatics and phylogenetic characterization of wheat showed the presence of 56 HSFs classifed into three groups—A, B, and C. The regulation of Plant HSFs basically takes place at transcriptional, post-transcriptional, translational, and post-translation levels. It also undergoes post-translational modifcations such as phosphorylation, ubiquitination, and Small Ubiquitin-like MOdifer (SUMO)-mediated degradation. The expression of Heat Shock Protein (HSP) genes in response to various stimuli is regulated by HSFs. HSF1 has been reported to be the master regulator for cytoprotective HSPs expression. HSF potentially bind and activate his own promoters as well as the promoters of other members of their gene family. HSFs perceive the elevation in temperature through different signaling molecules like H2O2, kinases and ultimately increase the expression of HSPs and other SAPs inside the cell in order to protect the nascent protein from denaturation. HSFs, being placed at pivotal position, needs to be further identifed, characterized and manipulated using the advanced genetic tools in order to regulate the expression of potential genes involved in defense mechanism of plants under stress. It can also be used as potential molecular marker in wheat breeding program.Not Availabl

Protection from terminal heat stress: a trade-off between heat-responsive transcription factors (HSFs) and stress-associated genes (SAGs) under changing environment

Terminal heat stress (HS) has adverse effect on the quantity and quality of wheat grains, as evident from the reduction in the yield. Plant has inherited tolerance mechanism to protect itself from the environmental stresses by modulating the expression and activity of stress associated genes (SAGs)/proteins (SAPs) which protect the plant from the damage caused by HS. Heat shock transcription factor (HSF) regulates the expression of SAGs in plant under HS. Bioinformatics and phylogenetic characterization of wheat showed the presence of 56 HSFs classified into three groups—A, B, and C. The regulation of Plant HSFs basically takes place at transcriptional, post-transcriptional, translational, and post-translation levels. It also undergoes post-translational modifications such as phosphorylation, ubiquitination, and Small Ubiquitin-like MOdifier (SUMO)-mediated degradation. The expression of Heat Shock Protein (HSP) genes in response to various stimuli is regulated by HSFs. HSF1 has been reported to be the master regulator for cytoprotective HSPs expression. HSF potentially bind and activate his own promoters as well as the promoters of other members of their gene family. HSFs perceive the elevation in temperature through different signaling molecules like H2O2, kinases and ultimately increase the expression of HSPs and other SAPs inside the cell in order to protect the nascent protein from denaturation. HSFs, being placed at pivotal position, needs to be further identified, characterized and manipulated using the advanced genetic tools in order to regulate the expression of potential genes involved in defense mechanism of plants under stress. It can also be used as potential molecular marker in wheat breeding program

Protection from terminal heat stress: a trade‑of between heat‑responsive transcription factors (HSFs) and stress‑associated genes (SAGs) under changing environment

Not AvailableTerminal heat stress (HS) has adverse effect on the quantity and quality of wheat grains, as evident from the reduction in the yield. Plant has inherited tolerance mechanism to protect itself from the environmental stresses by modulating the expression and activity of stress associated genes (SAGs)/proteins (SAPs) which protect the plant from the damage caused by HS. Heat shock transcription factor (HSF) regulates the expression of SAGs in plant under HS. Bioinformatics and phylogenetic characterization of wheat showed the presence of 56 HSFs classified into three groups—A, B, and C. The regulation of Plant HSFs basically takes place at transcriptional, post-transcriptional, translational, and post-translation levels. It also undergoes post-translational modifications such as phosphorylation, ubiquitination, and Small Ubiquitin-like MOdifier (SUMO)-mediated degradation. The expression of Heat Shock Protein (HSP) genes in response to various stimuli is regulated by HSFs. HSF1 has been reported to be the master regulator for cytoprotective HSPs expression. HSF potentially bind and activate his own promoters as well as the promoters of other members of their gene family. HSFs perceive the elevation in temperature through different signaling molecules like H2O2, kinases and ultimately increase the expression of HSPs and other SAPs inside the cell in order to protect the nascent protein from denaturation. HSFs, being placed at pivotal position, needs to be further identified, characterized and manipulated using the advanced genetic tools in order to regulate the expression of potential genes involved in defense mechanism of plants under stress. It can also be used as potential molecular marker in wheat breeding program.Not Availabl

Plant-parasitic nematodes of potential phytosanitary importance, their main hosts and reported yield losses

The potential phytosanitary importance of all named plant-parasitic nematode species was determined by evaluating available information on species characteristics, association with economically-important crop hosts, and ability to act as vectors of viruses or form disease complexes with other pathogens. Most named species of plant-parasitic nematodes (PPN) are poorly known, recorded from a single location only, not associated with economically-important crops, and not known to be associated with other plant disease organisms. However, 250 species from 43 genera fulfilled one or more of the criteria to be considered to present a phytosanitary risk. The genera and number of species (in parentheses) considered as posing phytosanitary risk included: Achlysiella (1), Anguina (8), Aphasmatylenchus (1), Aphelenchoides (12), Aphelenchus (1), Belonolaimus (2), Bitylenchus (3), Bursaphelenchus (4), Cactodera (3), Ditylenchus (8), Dolichodorus (1), Globodera (3), Helicotylenchus (7), Hemicriconemoides (3), Hemicycliophora (3), Heterodera (25), Hirschmanniella (5), Hoplolaimus (5), Ibipora (3), Longidorus (10), Macroposthonia (2), Meloidogyne (38), Merlinius (3), Nacobbus (1), Neodolichodorus (2), Paralongidorus (2), Paratrichodorus (11), Paratylenchus (3), Pratylenchus (24), Punctodera (3), Quinisulcius (3), Radopholus (5), Rotylenchulus (3), Rotylenchus (1), Scutellonema (5), Sphaeronema (1), Subanguina (3), Trichodorus (5), Tylenchorhynchus (8), Tylenchulus (2), Vittatidera (1), Xiphinema (15) and Zygotylenchus (1). For each of the 250 species main hosts and yield loss estimates are provided with an extensive bibliography. Of the 250 species, only 126 species from 33 genera are currently listed as regulated pests in one or more countries worldwide. Almost all of these 250 species were also associated with economically important crops and some also acted as vectors for viruses. © 2013 The Authors. Journal compilatio