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Nodule‐specific PLAT domain proteins are expanded in the Medicago lineage and required for nodulation
Author(s) -
Trujillo Diana I.,
Silverstein Kevin A. T.,
Young Nevin D.
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15697
Subject(s) - medicago truncatula , biology , lotus japonicus , gene , lineage (genetic) , genetics , root nodule , gene family , nodule (geology) , mutant , phenotype , microbiology and biotechnology , genome , symbiosis , bacteria , paleontology
Summary Symbiotic nitrogen fixation in legumes is mediated by an interplay of signaling processes between plant hosts and rhizobial symbionts. In legumes, several secreted protein families have undergone expansions and play key roles in nodulation. Thus, identifying lineage‐specific expansions ( LSE s) of nodulation‐associated genes can be a strategy to discover candidate gene families. Using bioinformatic tools, we identified 13 LSE s of nodulation‐related secreted protein families, each unique to either Glycine , Arachis or Medicago lineages. In the Medicago lineage, nodule‐specific Polycystin‐1, Lipoxygenase, Alpha Toxin ( PLAT ) domain proteins ( NPD s) expanded to five members. We examined NPD function using CRISPR /Cas9 multiplex genome editing to create Medicago truncatula NPD knockout lines, targeting one to five NPD genes. Mutant lines with differing combinations of NPD gene inactivations had progressively smaller nodules, earlier onset of nodule senescence, or ineffective nodules compared to the wild‐type control. Double‐ and triple‐knockout lines showed dissimilar nodulation phenotypes but coincided in upregulation of a DHHC ‐type zinc finger and an aspartyl protease gene, possible candidates for the observed disturbance of proper nodule function. By postulating that gene family expansions can be used to detect candidate genes, we identified a family of nodule‐specific PLAT domain proteins and confirmed that they play a role in successful nodule formation.