RRC ID 83914
Author Niranjan Mahadevan, Rozi Fernanda, Yusuke Kouzai, Natsuka Kohno, Reiko Nagao, Khin Thida Nyein, Megumi Watanabe, Nanami Sakata, Hidenori Matsui, Kazuhiro Toyoda, Yuki Ichinose, Keiichi Mochida, Hiroshi Hisano, Yoshiteru Noutoshi
Title Distinct Infection Mechanisms of Rhizoctonia solani AG-1 IA and AG-4 HG-I+II in Brachypodium distachyon and Barley
Journal Life
Abstract Rhizoctonia solani is a basidiomycete phytopathogenic fungus that causes rapid necrosis in a wide range of crop species, leading to substantial agricultural losses worldwide. The species complex is divided into 13 anastomosis groups (AGs) based on hyphal fusion compatibility and further subdivided by culture morphology. While R. solani classifications were shown to be independent of host specificity, it remains unclear whether different R. solani isolates share similar virulence mechanisms. Here, we investigated the infectivity of Japanese R. solani isolates on Brachypodium distachyon and barley. Two isolates, AG-1 IA (from rice) and AG-4 HG-I+II (from cauliflower), infected leaves of both plants, but only AG-4 HG-I+II infected roots. B. distachyon accessions Bd3-1 and Gaz-4 and barley cultivar ‘Morex’ exhibited enhanced resistance to both isolates compared to B. distachyon Bd21 and barley cultivars ‘Haruna Nijo’ and ‘Golden Promise’. During AG-1 IA infection, but not AG-4 HG-I+II infection, resistant Bd3-1 and Morex induced genes for salicylic acid (SA) and N-hydroxypipecolic acid (NHP) biosynthesis. Pretreatment with SA or NHP conferred resistance to AG-1 IA, but not AG-4 HG-I+II, in susceptible B. distachyon Bd21 and barley Haruna Nijo. On the leaves of susceptible Bd21 and Haruna Nijo, AG-1 IA developed extensive mycelial networks with numerous infection cushions, which are specialized infection structures well-characterized in rice sheath blight. In contrast, AG-4 HG-I+II formed dispersed mycelial masses associated with underlying necrosis. We propose that the R. solani species complex encompasses at least two distinct infection strategies: AG-1 IA exhibits a hemibiotrophic lifestyle, while AG-4 HG-I+II follows a predominantly necrotrophic strategy.
Volume 15
Pages 235
Published 2025-2-5
DOI 10.3390/life15020235
PMID 40003643
PMC PMC11856681
Resource
Barley Haruna Nijo