College of Agriculture, Yangtze University, Jingzhou 434025, China.
College of Agriculture, Yangtze University, Jingzhou 434025, China; Institute of Pesticides, Yangtze University, Jingzhou 434025, China.
Pestic Biochem Physiol. 2023 Aug;194:105502. doi: 10.1016/j.pestbp.2023.105502. Epub 2023 Jun 16.
Rice sheath blight caused by Rhizoctonia solani Kühn is a major fungal disease that plagues commercially grown rice. Occurring mainly in leaf sheaths and leaves, the disease leads to great losses in food production. β-amino-butyric acid (BABA) has been demonstrated to activate an induced resistance response and is a potent inducer of broad-spectrum disease resistance in different plant species. In this study, β-amino-butyric acid conjugate of phenazine-1-carboxylic acid (PCA) with prominent induced resistance to rice sheath blight was tested. The in vitro fungicidal activity, as well as in vivo efficacy, systemicity, induced resistance and defense enzyme activity of BABA conjugate of PCA against R. solani in rice seedlings was systematically evaluated. The results indicated that in vitro fungicidal activity of PCA-β-aminobutyric acid (4e) against R. solani was lower than that of PCA, but in vivo curative ability of 4e was the highest among all tested compounds. The systemicity tests in rice seedlings revealed that PCA did not possess phloem mobility, while 4e exhibited moderate phloem mobility but much lower thanα-amino-butyric acid conjugate of PCA (4d). In addition, Compound 4e showed the highest induced activity against rice sheath blight. The observed effects of defense enzymes help to explain this high level of induced activity. The current research results indicate that in rice seedlings, BABA conjugate of PCA induce observable resistance to rice sheath blight and exhibit moderate phloem mobility, which could be used as an induced resistance fungicide against rice sheath blight in commercial rice production. The BABA conjugate of PCA might provide a useful example of induced resistance to R. solani.
由立枯丝核菌引起的水稻纹枯病是一种严重的真菌病害，严重影响商业种植的水稻。该病害主要发生在叶片鞘和叶片上，导致粮食产量的巨大损失。β-氨基丁酸（BABA）已被证明能激活诱导抗性反应，是不同植物物种广谱抗病的有效诱导剂。在本研究中，测试了对水稻纹枯病具有显著诱导抗性的吩嗪-1-羧酸（PCA）的β-氨基丁酸缀合物。系统评估了 PCA-β-氨基丁酸缀合物（4e）对水稻幼苗中立枯丝核菌的体外杀菌活性、体内药效、系统性、诱导抗性和防御酶活性。结果表明，PCA-β-氨基丁酸（4e）对立枯丝核菌的体外杀菌活性低于 PCA，但在所有测试化合物中，4e 的体内治疗能力最高。在水稻幼苗中的系统性测试表明，PCA 不具有韧皮部移动性，而 4e 表现出中等的韧皮部移动性，但远低于 PCA 的α-氨基丁酸缀合物（4d）。此外，化合物 4e 对水稻纹枯病表现出最高的诱导活性。观察到的防御酶效应有助于解释这种高水平的诱导活性。目前的研究结果表明，在水稻幼苗中，PCA 的 BABA 缀合物能诱导对水稻纹枯病的可观察抗性，并表现出中等的韧皮部移动性，可作为商业水稻生产中防治水稻纹枯病的诱导抗性杀菌剂。PCA 的 BABA 缀合物可能为立枯丝核菌的诱导抗性提供一个有用的范例。
