小麦TaLCD基因的克隆及其对渗透胁迫的调节作用

半胱氨酸脱巯基酶(CDes)可催化降解半胱氨酸(Cys)生成硫化氢(H2S)。通过克隆小麦(Triticumaestivum)中的L-半胱氨酸脱巯基酶基因TaLCD,并将其在拟南芥(Arabidopsisthaliana)中过表达,探讨TaLCD对渗透胁迫条件下种子萌发和根系生长的影响,并分析其对干旱胁迫的调节作用。结果显示,盐胁迫条件下,TaLCD过表达植株种子萌发率显著高于野生型;甘露醇处理条件下,TaLCD过表达植株的根长也显著高于野生型,且TaLCD过表达显著提高植株抗旱性。此外,TaLCD过表达植株对ABA更加敏感,ABA处理下TaLCD过表达植株的种子萌发率及根长均显著低于野生型。干旱胁迫下,TaLCD过表达植株胁迫响应基因(COR47、RD29A、RAB18和RD22)及ABA信号途径相关基因(NCED3、HAB1、HAB2、ABI1、ABI2和ABF2)的表达水平均显著高于野生型。因此推测,TaLCD增强植株抗旱和抗盐能力可能依赖于ABA信号途径。

Cloning of Wheat TaLCD Gene and Its Regulation on Osmotic Stress

Cysteine desulphydrase (CDes) can degrade cysteine (Cys) to form hydrogen sulfide (H₂S). In this study, L-cysteine desulphydrase TaLCD from wheat (Triticum aestivum) was cloned and overexpressed in Arabidopsis thaliana. The effects of TaLCD on seed germination and root growth under osmotic stress in TaLCD overexpressing plants were examined, and the response to drought stress was also investigated. The results showed that, the seed germination rate of TaLCD overexpressing plants under salt treatment was remarkably higher than the wild type (WT), and the root length of TaLCD overexpressing plants was obviously longer when exposed to mannitol. Moreover, overexpression of TaLCD distinctly increased plant drought resistance. In addition, TaLCD overexpressing plants were more sensitive to ABA, with decreased seed germination rate and root length under ABA treatment. Furthermore, the expression of stress-responsive genes (COR47, RD29A, RAB18 and RD22) and ABA signaling pathway-related genes (NCED3, HAB1, HAB2, ABI1, ABI2 and ABF2) was significantly higher in TaLCD overexpressing plants than that in WT under drought stress. These results suggest that TaLCD enhances the drought and salt tolerance of plants possibly by ABA signaling pathway.