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NODULES WITH ACTIVATED DEFENSE 1 is required for maintenance of rhizobial endosymbiosis in Medicago truncatula
Author(s) -
Wang Chao,
Yu Haixiang,
Luo Li,
Duan Liujian,
Cai Liuyang,
He Xinxing,
Wen Jiangqi,
Mysore Kirankumar S.,
Li Guoliang,
Xiao Aifang,
Duanmu Deqiang,
Cao Yangrong,
Hong Zonglie,
Zhang Zhongming
Publication year - 2016
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.14017
Subject(s) - medicago truncatula , endosymbiosis , biology , medicago , symbiosis , botany , paleontology , biochemistry , gene , bacteria , plastid , chloroplast
Summary The symbiotic interaction between legume plants and rhizobia results in the formation of root nodules, in which symbiotic plant cells host and harbor thousands of nitrogen‐fixing rhizobia. Here, a Medicago truncatula nodules with activated defense 1 ( nad1 ) mutant was identified using reverse genetics methods. The mutant phenotype was characterized using cell and molecular biology approaches. An RNA ‐sequencing technique was used to analyze the transcriptomic reprogramming of nad1 mutant nodules. In the nad1 mutant plants, rhizobial infection and propagation in infection threads are normal, whereas rhizobia and their symbiotic plant cells become necrotic immediately after rhizobia are released from infection threads into symbiotic cells of nodules. Defense‐associated responses were detected in nad1 nodules. NAD 1 is specifically present in root nodule symbiosis plants with the exception of Morus notabilis , and the transcript is highly induced in nodules. NAD 1 encodes a small uncharacterized protein with two predicted transmembrane helices and is localized at the endoplasmic reticulum. Our data demonstrate a positive role for NAD 1 in the maintenance of rhizobial endosymbiosis during nodulation.