Suwanchaikasem Pipob, Nie Shuai, Selby-Pham Jamie, Walker Robert, Boughton Berin A, Idnurm Alexander
School of BioSciences University of Melbourne Melbourne Victoria Australia.
Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute University of Melbourne Melbourne Victoria Australia.
Plant Direct. 2023 Sep 8;7(9):e528. doi: 10.1002/pld3.528. eCollection 2023 Sep.
Southern blight disease, caused by the fungal pathogen , suppresses plant growth and reduces product yield in agriculture. Mechanisms of pathology of this soil-borne disease remain poorly understood, with disease management strategies reliant upon broad-spectrum antifungal use. Exposure to chitosan, a natural elicitor, has been proposed as an alternative method to control diverse fungal diseases in an eco-friendly manner. In this study, plants were grown in the Root-TRAPR system, a transparent hydroponic growth device, where plant roots were primed with .2% colloidal chitosan prior to inoculation. Both chitosan-primed and unprimed inoculated plants displayed classical symptoms of wilting and yellowish leaves, indicating successful infection. Non-primed infected plants showed increased shoot defense responses with doubling of peroxidase and chitinase activities. The levels of growth and defense hormones including auxin, cytokinin, and jasmonic acid were increased 2-5-fold. In chitosan-primed infected plants, shoot peroxidase activity and phytohormone levels were decreased 1.5-4-fold relative to the unprimed infected plants. When compared with shoots, roots were less impacted by infection, but the pathogen secreted cell wall-degrading enzymes into the root-growth solution. Chitosan priming inhibited root growth, with root lengths of chitosan-primed plants approximately 65% shorter than the control, but activated root defense responses, with root peroxidase activity increased 2.7-fold along with increased secretion of defense proteins. The results suggest that chitosan could be an alternative platform to manage southern blight disease in cultivation; however, further optimization is required to maximize effectiveness of chitosan.
由真菌病原体引起的南方疫病会抑制植物生长并降低农业产量。这种土传病害的病理机制仍知之甚少，疾病管理策略依赖于广谱抗真菌药物的使用。壳聚糖作为一种天然激发子，已被提议作为一种以生态友好方式控制多种真菌病害的替代方法。在本研究中，植物在Root-TRAPR系统（一种透明水培生长装置）中生长，在接种前用0.2%的胶体壳聚糖对植物根系进行预处理。经壳聚糖预处理和未经预处理接种的植物均表现出典型的萎蔫和叶片发黄症状，表明感染成功。未经预处理的感染植物表现出地上部防御反应增强，过氧化物酶和几丁质酶活性加倍。包括生长素、细胞分裂素和茉莉酸在内的生长和防御激素水平增加了2至5倍。在经壳聚糖预处理的感染植物中，地上部过氧化物酶活性和植物激素水平相对于未经预处理的感染植物降低了1.5至4倍。与地上部相比，根系受感染的影响较小，但病原体向根系生长溶液中分泌细胞壁降解酶。壳聚糖预处理抑制根系生长，经壳聚糖预处理的植物根长比对照短约65%，但激活了根系防御反应，根系过氧化物酶活性增加了2.7倍，同时防御蛋白分泌增加。结果表明，壳聚糖可能是一种在栽培中管理南方疫病的替代平台；然而，需要进一步优化以最大限度地提高壳聚糖的有效性。
