Loss of the accessory chromosome converts a pathogenic tree-root fungus into a mutualistic endophyte  

作　　者：Huanshen Wei Zhenhui Zhong Zhongfeng Li Yuwei Zhang Eva H.Stukenbrock Boping Tang Ningning Yang Riccardo Baroncelli Long Peng Zhuo Liu Xinghua He Yuzhan Yang Zhilin Yuan 

机构地区：[1]State Key Laboratory of Tree Genetics and Breeding,Chinese Academy of Forestry,Beijing 100091,China [2]Research Institute of Subtropical Forestry,Chinese Academy of Forestry,Hangzhou 311400,China [3]State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops,Fujian Agriculture and Forestry University,Fuzhou 350002,China [4]Environmental Genomics,Christian-Albrechts University,24118 Kiel,Germany [5]Max Planck Fellow Group Environmental Genomics,Max Planck Institute for Evolutionary Biology,24306 Plon,Germany [6]Jiangsu Key Laboratory for Bioresources of Saline Soils,School of Wetlands,Yancheng Teachers University,Yancheng 224002,China [7]Department of Agricultural and Food Sciences(DISTAL),University of Bologna,40127 Bologna,Italy

出　　处：《Plant Communications》2024年第1期164-180,共17页植物通讯（英文）

基　　金：supported by the National Key Research and Development Program of China (2022YFD2201900);the National Natural Science Foundation of China (no.31722014).

摘　　要：Some fungal accessory chromosomes(ACs)may contribute to virulence in plants.However,the mecha-nisms by which ACs determine specific traits associated with lifestyle transitions along a symbiotic contin-uum are not clear.Here we delineated the genetic divergence in two sympatric but considerably variable isolates(16B and 16W)of the poplar-associated fungus Stagonosporopsis rhizophilae.We identified a-0.6-Mb horizontally acquired AC in 16W that resulted in a mildly parasitic lifestyle in plants.Complete deletion of the AC(D16W)significantly altered the fungal phenotype.Specifically,D16W was morphologically more similar to 16B,showed enhanced melanization,and established beneficial interactions with poplar plants,thereby acting as a dark septate endophyte.RNA sequencing(RNA-seq)analysis showed that AC loss induced the upregulation of genes related to root colonization and biosynthesis of indole acetic acid and melanin.We observed that the AC maintained a more open status of chromatin across the genome,indicating an impressive remodeling of cis-regulatory elements upon AC loss,which potentially enhanced symbiotic effectiveness.We demonstrated that the symbiotic capacities were non-host-specific through comparable experiments on Triticum–and Arabidopsis–fungus associations.Furthermore,the three isolates generated symbiotic interactions with a nonvascular liverwort.In summary,our study suggests that the AC is a suppressor of symbiosis and provides insights into the underlying mechanisms of mutualism with vascular plants in the absence of traits encoded by the AC.We speculate that AC-situ-ated effectors and other potential secreted molecules may have evolved to specifically target vascular plants and promote mild virulence.

关 键 词：dark septate endophytes EFFECTORS lifestyle transition root–fungus symbioses 

分 类 号：Q94[生物学—植物学]