A chloroplast‐localized protein LESION AND LAMINA BENDING affects defence and growth responses in rice

Abstract

SummaryUnderstanding how plants allocate their resources to growth or defence is of long-term importance to the development of new and improved varieties of different crops.Using molecular genetics, plant physiology, hormone analysis and Next-Generation Sequencing (NGS)-based transcript profiling, we have isolated and characterized the rice (Oryza sativa) LESION AND LAMINA BENDING (LLB) gene that encodes a chloroplasttargeted putative leucine carboxyl methyltransferase.Loss of LLB function results in reduced growth and yield, hypersensitive response (HR)-like lesions, accumulation of the antimicrobial compounds momilactones and phytocassanes, and constitutive expression of pathogenesis-related genes. Consistent with these defenceassociated responses, llb shows enhanced resistance to rice blast (Magnaporthe oryzae) and bacterial blight (Xanthomonas oryzae pv. oryzae). The lesion and resistance phenotypes are likely to be caused by the over-accumulation of jasmonates (JAs) in the llb mutant including the JA precursor 12-oxo-phytodienoic acid. Additionally, llb shows an increased lamina inclination and enhanced early seedling growth due to elevated brassinosteroid (BR) synthesis and/or signalling.These findings show that LLB functions in the chloroplast to either directly or indirectly repress both JA-and BR-mediated responses, revealing a possible mechanism for controlling how plants allocate resources for defence and growth.

Commonly and Specifically Activated Defense Responses in Maize Disease Lesion Mimic Mutants Revealed by Integrated Transcriptomics and Metabolomics Analysis

“…With the development of high-throughput transcriptomic and metabolomic techniques, the gene expression and metabolomic changes can be monitored simultaneously in order to dissect the underlying signaling and biochemical pathways in respect to specific traits (Li et al, 2010;Chen et al, 2014;Tamiru et al, 2016;Kaling et al, 2018;Mcloughlin et al, 2018;Wang et al, 2018;Castro-Moretti et al, 2020). Although Les/les mutants are considered invaluable models to dissect defense mechanisms, there is a lack of systemic characterization of maize Les mutants by multi-omics analysis.…”

Mutation in Rice Abscisic Acid2 Results in Cell Death, Enhanced Disease-Resistance, Altered Seed Dormancy and Development

“…The lesion mimic mutants (LMMs) display cell death, similar to hypersensitive response (HR), and are highly valuable in the investigation of the molecular mechanism of programmed cell death and defense responses ( Greenberg, 1997 ; Moeder and Yoshioka, 2008 ; Tamiru et al, 2016 ). A number of LMMs have been isolated and characterized in Arabidopsis ( Cao et al, 1994 ), maize ( Hu et al, 1998 ), barley ( Persson et al, 2009 ), and rice ( Kiyosawa, 1970 ; Liu et al, 2017 ).…”

Comparative proteomic analysis reveals alterations in development and photosynthesis-related proteins in diploid and triploid rice

“…The critical role of chloroplasts is beyond dispute and has been reported in plant immunity recently [ 28 , 29 ]. Recently, a chloroplast-localized protein LLB was found to affect the growth in rice [ 30 ]. Although it is well known that chloroplast affects the growth of rice, the underlying molecular mechanisms are not yet understood clearly.…”