Department of Molecular Biology & Genetic Engineering, College of Basic Sciences & Humanities, G.B. Pant University of Agriculture & Technology, Pantnagar, Uttarakhand India.
Plant Signal Behav. 2011 Jun;6(6):821-30. doi: 10.4161/psb.6.6.14743.
Two wheat varieties HD-29 (resistant, R) and WH-542 (susceptible, S) were pretreated with jasmonic acid (JA) or jasmonate and then artificially inoculated with sporidial suspension of Tilletia indica to study its influence in reducing Karnal bunt (KB) infection by regulating cystatin gene expression. JA was found to improve the plant defense against KB as its exogenous application resulted in decrease in coefficient of infection (CI) in both susceptible and resistant varieties following pathogen inoculation. Transcript profiling of wheat cystatin genes at different days after inoculation (DAI) showed that JA pretreatment positively induced cystatin gene expression in both varieties with greater induction of expression in resistant variety than the susceptible one (P< 0.05). Different temporal expression of three wheat cystatin genes, WC2, WC3 and WCMD was observed with their increased expression at 1DAI in the boot emergence stage which is most susceptible to KB and then slowly declined gradually at 3, 7 and 15 DAI in both the varieties. Except WC2, higher expression of other two cystatins viz. WC3 and WCMD at 1DAI showed higher response (P< 0.05) to KB pathogenesis at the disease-prone boot emergence stage as also evident by decrease of CI in both varieties. The results of determination of specific activity of cystatin by inhibitor assay were found to be consistent with those of transcript profiling. These findings suggest that jasmonic acid (JA) may act as a potential activator of induced resistance against Karnal bunt of wheat by upregulating cystatin gene expression.
两种小麦品种 HD-29（抗性，R）和 WH-542（敏感，S）用茉莉酸（JA）或茉莉酸盐预处理，然后用印度腥黑粉菌的孢子悬浮液人工接种，研究其通过调节半胱氨酸蛋白酶抑制剂基因表达来减轻小麦印度腥黑穗病（KB）感染的影响。发现 JA 能改善植物对 KB 的防御能力，因为其外源应用导致在接种病原菌后，两种敏感和抗性品种的感染系数（CI）都降低。接种后不同天数（DAI）小麦半胱氨酸蛋白酶抑制剂基因的转录谱分析表明，JA 预处理能在两种品种中正向诱导半胱氨酸蛋白酶抑制剂基因的表达，且在抗性品种中的诱导表达高于敏感品种（P<0.05）。观察到三种小麦半胱氨酸蛋白酶抑制剂基因 WC2、WC3 和 WCMD 的不同时间表达，在 boot 萌发阶段（对 KB 最敏感），它们的表达在 1DAI 时增加，然后在两种品种中，在 3、7 和 15 DAI 时逐渐缓慢下降。除 WC2 外，其他两种半胱氨酸蛋白酶抑制剂 WC3 和 WCMD 在 1DAI 时的高表达显示出对 KB 发病机制的更高响应（P<0.05），在两种品种中，CI 的降低也很明显。抑制剂测定法测定半胱氨酸蛋白酶抑制剂的比活度的结果与转录谱分析的结果一致。这些发现表明，茉莉酸（JA）可能通过上调半胱氨酸蛋白酶抑制剂基因的表达，作为诱导小麦对 KB 抗性的潜在激活剂。
