Comparing the infection biology and gene expression differences of primary and secondary zoospores.
Hui Yang, Qianyu Sun, Yihan Zhang, Yang Zhang, Yushan Zhao, Xinyue Wang, Yanmei Chen, Shu Yuan, Junbo Du, Wenming Wang
Author Information
Hui Yang: College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Qianyu Sun: College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Yihan Zhang: College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Yang Zhang: College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Yushan Zhao: College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Xinyue Wang: National Demonstration Center for Experimental Crop Science Education, College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Yanmei Chen: College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Shu Yuan: College of Resources, Sichuan Agricultural University, Chengdu, China.
Junbo Du: College of Agronomy, Sichuan Agricultural University, Chengdu, China.
Wenming Wang: State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, China.
(Wor.) is an obligate plant pathogen affecting Brassicae worldwide. To date, there is very little information available on the biology and molecular basis of primary and secondary zoospore infections. To examine their roles, we used microscope to systematically investigate the infection differences of between samples inoculated separately with resting spores and secondary zoospores. The obvious development of asynchrony that is characterized by secondary plasmodium, resting sporangial plasmodium, and resting spores was observed at 12 days in inoculated with resting spores but not when inoculated with secondary zoospores at the same time. Inoculation with resting spores resulted in much more development of zoosporangia clusters than inoculation with secondary zoospores in non-host . The results indicated that primary zoospore infection played an important role in the subsequent development. To improve our understanding of the infection mechanisms, RNA-seq analysis was performed. Among 18 effectors identified in , 13 effectors were induced in seedlings inoculated with resting spores, which suggested that the pathogen and host first contacted, and more effectors were needed. Corresponding to those in , the expression levels of most genes involved in the calcium-mediated signaling pathway and PTI pathway were higher in plants inoculated with resting spores than in those inoculated with secondary zoospores. The ETI pathway was suppressed after inoculation with secondary zoospores. The genes induced after inoculation with resting spores were suppressed in seedlings inoculated with secondary zoospores, which might be important to allow a fully compatible interaction and contribute to a susceptible reaction in the host at the subsequent infection stage. The primary zoospores undertook an more important interaction with plants.
