Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, Telangana, India.
Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, 500046, Telangana, India.
Carbohydr Res. 2021 Dec;510:108459. doi: 10.1016/j.carres.2021.108459. Epub 2021 Oct 9.
Long-chain chitooligosaccharides (COS) with degree of polymerization (DP) more than 4 are known to have potential biological activities. A hyper-transglycosylating mutant of an endo-chitinase from Serratia proteamaculans (SpChiD-Y28A) was used to synthesize COS with DP6 and DP7 using COS DP5 as substrate. Purified COS with DP5-7 were tested to elicit the defense response in rice seedlings. Among the COS used, DP7 strongly induced oxidative burst response as well as peroxidase, and phenylalanine ammonia lyase activites. A few selected marker genes in salicylic acid (SA)- and jasmonic acid-dependent pathways were evaluated by real-time PCR. The expression levels of pathogenesis-related (PR) genes PR1a and PR10 and defense response genes (chitinase1, peroxidase and β -1,3-glucanase) were up regulated upon COS treatment in rice seedlings. The DP7 induced Phenylalanine ammonia lyase and Isochorismate synthase 1 genes, with concomitant increase of Mitogen-activated protein kinase 6 and WRKY45 transcription factor genes indicated the possible role of phosphorylation in the transmission of a signal to induce SA-mediated defense response in rice.
具有聚合度（DP）超过 4 的长链壳寡糖（COS）已知具有潜在的生物活性。使用来自变形沙雷氏菌（Serratia proteamaculans）的内切几丁质酶的高转糖苷突变体（SpChiD-Y28A），以 COS DP5 为底物合成 DP6 和 DP7 的 COS。测试 DP5-7 的纯化 COS 以在水稻幼苗中引发防御反应。在所使用的 COS 中，DP7 强烈诱导氧化爆发反应以及过氧化物酶和苯丙氨酸解氨酶活性。通过实时 PCR 评估了水杨酸（SA）和茉莉酸依赖性途径中的几个选定标记基因。在水稻幼苗中，用 COS 处理后，病程相关（PR）基因 PR1a 和 PR10 以及防御反应基因（几丁质酶 1、过氧化物酶和β-1,3-葡聚糖酶）的表达水平上调。DP7 诱导苯丙氨酸解氨酶和异分支酸合酶 1 基因，同时伴随着丝裂原激活蛋白激酶 6 和 WRKY45 转录因子基因的增加，表明磷酸化在向水稻传递信号以诱导 SA 介导的防御反应中可能发挥作用。
