การโคลนนิ่งและหาลำดับเบสของยีนที่ตอบสนองต่อสภาวะแล้งและความสัมพันธ์ระหว่างลักษณะโครงสร้างทางกายวิภาคกับการทนทานต่อสภาพแล้งในข้าวโพด (Zea mays L.)

Abstract

Drought stress could induce expressions of various genes that are involved in stress tolerance and responses. Recent studies were emphasized on a gene encoded for the 9-cis epoxycarotenoid dioxygenase (NCED) enzyme which catalyzes the biosynthesis of abscisic acid (ABA) in plants. However, little is known about drought tolerance genes in maize. We designed primers from the VP14 sequence in the NCBI gene bank for the study of expression of drought tolerance gene in SW 2301 drought tolerant and KSX 4605 drought sensitive lines. The RT-PCR showed an expression of drought responsible gene in SW 2301 drought tolerant line. Under drought condition, the expression of the responsible gene was higher in stem apical meristem than in root and leaf tissues. The cDNA of this gene was cloned by rapid amplification of cDNA ends (RACE). The full-length sequence of this drought responsible gene was 1607 bp with the open reading frame at 56-1345 bp. Anatomical characteristics relating to water utilization including stomata, bulliform cell, vascular bundle and vessel were investigated in 5 varieties of corn. It was found that the drought tolerant variety had a small number of stomata, a large number of vascular bundle and a large size of vessel. Among the five varieties (Ki 3, Ki 11, Ki 20, Suwan 2301 and Insee), Ki 11 variety showed the smallest number of stomata, the largest number of vascular bundle and the largest size of vessel. Overall of this study, it can be concluded that Ki 11 is the best drought tolerant variety followed by Ki 20 variety whilst Ki 3 variety showed the most susceptible to drought.