Ahmad Ikhlaq, Rana Rashid Mehmood, Hassan Mahmood Ul, Khan Muhammad Azam, Sajjad Muhammad
Department of Plant Breeding and Genetics, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan.
Department of Horticulture, PMAS-Arid Agriculture University, Rawalpindi, 46300, Pakistan.
Mol Biol Rep. 2022 Dec;49(12):11409-11419. doi: 10.1007/s11033-022-07827-x. Epub 2022 Aug 12.
Considerable production losses are caused by heat and drought stress in okra. Germplasm evaluation at genetic level is essential for the selection of promising genotypes. Lack of genomic information of okra limits the use of genetic markers. However, syntenic markers of some related family could be used for molecular characterization of major economic traits.
Herein, 56 okra genotypes were evaluated for drought and heat tolerance. Sixty-one expressed sequence tags (ESTs) identified for heat and drought tolerance in cotton were searched from literature surveys and databases. The identified ESTs were BLAST searched into okra unigene database. Primers of selected okra unigenes were synthesized and amplified in all genotypes using standard polymerase chain reaction (PCR) protocol. Marker trait association (MTA) of the syntenic unigenes were identified between genotypic and phenotypic data on the basis of linkage disequilibrium Functional syntenic analysis revealed that out of these 61 cotton ESTs 55 had functional homology with okra unigenes. These 55 unigenes were used as markers for further analysis (amplification). Okra genotypes showed significance variations for all the physo-morphological parameters under heat and drought stress. Genotypes Perbhani Karanti, IQRA-III, Selection Super Green, Anmol and Line Bourd performed better under drought stress whereas genotypes Perbhani Karanti, IQRA-III, Green Gold, OK-1501 and Selection Super Green showed heat tolerance. Fifty markers showed amplification in okra. Fifty-six okra genotypes were clustered into three distinct populations. LD analysis has shown most significant linkage between markers Unigene43786 and Unigene3662. MTAs using MLM and GLM models revealed that 23 markers have significant associations (p < 0.05) with different traits under control and stressed conditions. Relative water content is associated with four markers (Unigene10673, Unigene99547, Unigene152901, and Unigene129684) under drought conditions. Whereas, Electrolyte leakage was associated with 3 markers (Unigene109922, Unigene28667 and Unigene146907) under heat stress.
These identified unigenes may be helpful in the development of drought and heat tolerant genotypes in okra.
秋葵的高温和干旱胁迫会导致大量产量损失。在基因水平上进行种质评估对于筛选有潜力的基因型至关重要。秋葵基因组信息的缺乏限制了遗传标记的应用。然而，一些相关科的共线性标记可用于主要经济性状的分子鉴定。
本文对56个秋葵基因型进行了耐旱性和耐热性评估。通过文献调研和数据库搜索，确定了61个在棉花中鉴定出的与耐热性和耐旱性相关的表达序列标签（EST）。将鉴定出的EST在秋葵单基因数据库中进行BLAST搜索。合成选定秋葵单基因的引物，并使用标准聚合酶链反应（PCR）方案在所有基因型中进行扩增。基于连锁不平衡，在基因型和表型数据之间鉴定共线性单基因的标记-性状关联（MTA）。功能共线性分析表明，这61个棉花EST中有55个与秋葵单基因具有功能同源性。这55个单基因被用作进一步分析（扩增）的标记。秋葵基因型在高温和干旱胁迫下所有生理形态参数均表现出显著差异。Perbhani Karanti、IQRA-III、Selection Super Green、Anmol和Line Bourd基因型在干旱胁迫下表现较好，而Perbhani Karanti、IQRA-III、Green Gold、OK-1501和Selection Super Green基因型表现出耐热性。50个标记在秋葵中显示出扩增。56个秋葵基因型被聚类为三个不同的群体。连锁不平衡分析表明，标记Unigene43786和Unigene3662之间存在最显著的连锁。使用混合线性模型（MLM）和广义线性模型（GLM）的MTA分析表明，23个标记在对照和胁迫条件下与不同性状存在显著关联（p < 0.05）。在干旱条件下，相对含水量与4个标记（Unigene10673、Unigene99547、Unigene152901和Unigene129684）相关。而在热胁迫下，电解质渗漏与3个标记（Unigene109922、Unigene28667和Unigene146907）相关。
这些鉴定出的单基因可能有助于秋葵耐旱和耐热基因型的培育。
