Large-Scale Screening and Function Analysis of Rhizoctonia solani Effectors Targeting Rice Chloroplasts

Rice sheath blight (RSB), caused byRhizoctonia
solani, is a major economic threat to global rice
crops. The genome of R. solani contains
over 103 potential effectors,
with most functions still unknown. Previous studies show that chloroplast
plays a crucial role in RSB resistance. However, whether R. solani effectors target plant chloroplasts to
promote the pathogen infection remains unclear. This study leveraged
four RSB-resistant chloroplast proteins to identify five interacting
secreted proteins from a 430-protein R. solani yeast library. These proteins, which localize to rice chloroplasts,
were shown to cause cell death in Nicotiana benthamiana and rice protoplasts, suggesting that they potentially influence
host cellular processes by targeting chloroplasts. Bioinformatic analysis
indicates that these five putative effectors almost all contained
conserved structures related to pathogenicity. This study provides
a novel method for screening specific functional effectors and facilitates
the further study of the pathogenic mechanisms of R.
solani.