Devate Narayana Bhat, Krishna Hari, Mishra Chandra Nath, Manjunath Karthik Kumar, Sunilkumar V P, Chauhan Divya, Singh Shweta, Sinha Nivedita, Jain Neelu, Singh Gyanendra Pratap, Singh Pradeep Kumar
Division of Genetics, ICAR-Indian Agricultural research institute, New Delhi, India.
ICAR- Indian Institute of Wheat and Barley Research, Karnal, India.
Front Plant Sci. 2023 Jan 16;13:1082513. doi: 10.3389/fpls.2022.1082513. eCollection 2022.
Wheat 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.
A 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.
Three 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). 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.
小麦在全球范围内种植和消费，因其热量和营养成分而成为重要的主食作物。在以小麦为主食的地区，微量营养素含量水平不理想，尤其是谷物中铁（Fe）和锌（Zn）的含量，可能导致营养不良。谷物养分含量受干旱和热胁迫等非生物胁迫的影响。解决微量营养素缺乏的最佳方法是对粮食作物进行生物强化。标记辅助品种培育的前提是确定负责高谷物铁和锌含量的基因组区域，并了解其遗传学。
在新德里的印度农业研究机构（IARI），于不同年份在适时播种灌溉（IR）、限制灌溉（RI）和晚播（LS）条件下，对193种不同的小麦基因型进行干旱和热胁迫条件下的评估。从对照组和处理组中估计谷物铁含量（GFeC）和谷物锌含量（GZnC）。使用来自育种者35K公理阵列的单核苷酸多态性（SNP）对所有研究品系进行基因分型。
基于主成分分析（PCA）和聚类分析，在关联面板中观察到三个亚组。观察到一个3.49 Mb的大的全基因组连锁不平衡（LD）块大小。全基因组关联研究确定了16个与GFeC、GZnC和千粒重（TGW）相关的独特严格标记性状关联。分析表明，在16个连锁SNP的侧翼区域存在28个潜在候选基因，如突触结合蛋白样线粒体脂质结合结构域、HAUS augmin样复合体、含双铜中心结构域、蛋白激酶、伴侣蛋白Cpn60、锌指、NUDIX水解酶等。还发现了这些基因在营养组织和谷物中的表达水平。在标记辅助育种中利用已鉴定的标记可能会导致生物强化小麦基因型的快速培育，以对抗营养不良。
