Soybean Genomics and Improvement Laboratory, Agricultural Research Service, USDA, Beltsville, MD, USA.
Department of Cell Biology and Molecular Genetics, Bioscience Research Bldg, University of Maryland, MD, USA.
J Exp Bot. 2018 May 25;69(12):3009-3021. doi: 10.1093/jxb/ery135.
INFLORESCENCE DEFICIENT IN ABSCISSION (IDA) is a signaling peptide that regulates cell separation in Arabidopsis including floral organ abscission and lateral root emergence. IDA is highly conserved in dicotyledonous flowering plant genomes. IDA-like sequences were also found in the genomic sequences of root-knot nematodes, Meloidogyne spp., which are globally deleterious pathogens of agriculturally important plants, but the role of these genes is unknown. Exogenous treatment of the Arabidopsis ida mutant with synthetic peptide identical to the M. incognita IDA-like 1 (MiIDL1) protein sequence minus its N-terminal signal peptide recovered both the abscission and root architecture defects. Constitutive expression of the full-length MiIDL1 open reading frame in the ida mutant substantially recovered the delayed floral organ abscission phenotype whereas transformants expressing a construct missing the MiIDL1 signal peptide retained the delayed abscission phenotype. Importantly, wild-type Arabidopsis plants harboring an MiIDL1-RNAi construct and infected with nematodes had approximately 40% fewer galls per root than control plants. Thus, the MiIDL1 gene produces a functional IDA mimic that appears to play a role in successful gall development on Arabidopsis roots.
褪绿败育（IDA）是一种信号肽，可调节拟南芥中的细胞分离，包括花器官脱落和侧根萌发。IDA 在双子叶开花植物基因组中高度保守。在根结线虫（Meloidogyne spp.）的基因组序列中也发现了与 IDA 相似的序列，根结线虫是对农业重要植物具有全球危害性的病原体，但这些基因的作用尚不清楚。用与 M. incognita IDA-like 1（MiIDL1）蛋白序列相同的合成肽（减去其 N 端信号肽）对拟南芥 ida 突变体进行外源处理，恢复了脱落和根系结构缺陷。在 ida 突变体中组成型表达全长 MiIDL1 开放阅读框，实质上恢复了延迟的花器官脱落表型，而表达缺失 MiIDL1 信号肽的转化体则保留了延迟的脱落表型。重要的是，携带 MiIDL1-RNAi 构建体并感染线虫的野生型拟南芥植物的根瘤数比对照植物减少了约 40%。因此，MiIDL1 基因产生了一种功能性的 IDA 模拟物，它似乎在拟南芥根部成功发育根瘤中发挥作用。
