Abstract
Arbuscular mycorrhizal symbiosis (AMS) is widespread mutualistic association between plants and fungi, which plays an essential role in nutrient exchange, enhancement in plant stress resistance, development of host, and ecosystem sustainability. Previous studies have shown that plant small secreted proteins (SSPs) are involved in beneficial symbiotic interactions. However, the role of SSPs in the evolution of AMS has not been well studied yet. In this study, we performed computational analysis of SSPs in 60 plant species and identified three AMS-specific ortholog groups containing SSPs only from at least 30% of the AMS species in this study and three AMS-preferential ortholog groups containing SSPs from both AMS and non-AMS species, with AMS species containing significantly more SSPs than non-AMS species. We found that independent lineages of monocot and eudicot plants contained genes in the AMS-specific ortholog groups and had significant expansion in the AMS-preferential ortholog groups. Also, two AMS-preferential ortholog groups showed convergent changes, between monocot and eudicot species, in gene expression in response to arbuscular mycorrhizal fungus Rhizophagus irregularis. Furthermore, conserved cis-elements were identified in the promoter regions of the genes showing convergent gene expression. We found that the SSPs, and their closely related homologs, in each of three AMS-preferential ortholog groups, had some local variations in the protein structural alignment. We also identified genes co-expressed with the Populus trichocarpa SSP genes in the AMS-preferential ortholog groups. This first plant kingdom-wide analysis on SSP provides insights on plant-AMS convergent evolution with specific SSP gene expression and local diversification of protein structures.
Original language | English |
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Article number | uhac043 |
Journal | Horticulture Research |
Volume | 9 |
DOIs | |
State | Published - 2022 |
Funding
The research was supported by the Laboratory Directed Research and Development program of Oak Ridge National Laboratory, and by the U.S. Department of Energy, Office of Biological and Environmental Research (BER) in the Office of Science, BER Genomic Science Program, as part of the Secure Ecosystem Engineering and Design and the Plant-Microbe Interfaces Scientific Focus Areas. Oak Ridge National Laboratory is managed by UTBattelle, LLC, for the United States Department of Energy under contract DE-AC05-00OR22725. X.-L.H. received financial support from the China Scholarship Council. J.Z. was supported by Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding (2021C02070-1), the National Science Foundation of China (32171814), and the Zhejiang A&F University Research and Development Fund Talent Startup Project (2021LFR013).