Evaluation of Drought Stress-responsive Genes Expression of Durum Wheat Using Comparative Genomics

As the water resources become more limited, the production levels of crops are declining, and following the rapid increase in population, the use of mankind from staple food products has increased. So, the development of drought-tolerant crops aimed at cultivation in the arid regions will be of great worth to provide the country's nutritional necessity. The following research aimed to elucidate the drought tolerance of durum wheat (Triticum turgidum ssp. durum) through comparative expressed sequence tags/EST analysis of unstressed library with ۲۵۳۴ EST and drought-stressed library with ۴۴۸۵ EST. Preliminary data were gathered from the Harvard university database. All unigenes were assembled using EGassembler software to detect similarities between the two libraries and were then analyzed through X-blast by CLCbio software against a non-redundant protein database. To identify statistically differentially expressed genes, the IDEG۶ web tool was used. Over ۱۵۰ differentially ESTs were detected by Audic-Claverie statistics of IDEG۶ software, in which over ۸۵% ESTs were upregulated in response to drought. The GoMapMan comparative classification tool was used to categorize gene functional annotations. All significant differential unigenes were divided into seven functional categories i.e., photosynthesis and energy (۱۹%), regulatory pathways (۲۵%), transport (۵%), hormones, plant defense, response to drought stress (۱۱%), cell metabolism (۱۹%), cell organization and development (۴%) and miscellaneous as well as unclassified processes (۱۷%). Comparative analysis revealed that some of the promising traits in T. turgidum are specifically regulated in drought stress including genes related to response to stress and hormones pathways, development and growth (helicases and CPL phosphatase), maintenance of cell water content (transporters and osmolites), membrane stability (HSP) and preventing the accumulation of toxins. This study prominently demonstrates the helicase role under durum wheat’s drought tolerance as well as provides indices for assessing the drought tolerance of T. turgidum aims to the use of tolerant varieties in breeding programs in arid and semi-arid regions in Iran.

Keywords:

Comparative genomics , Drought-tolerant cultivar , Expressed sequence tags , Functional catalogs , Gene expression analysis , Physiological processes