NARROW AND ROLLED LEAF 2 regulates leaf shape, male fertility, and seed size in rice

J Integr Plant Biol. 2016 Dec;58(12):983-996. doi: 10.1111/jipb.12503. Epub 2016 Nov 23.

Abstract

Grain yield in rice (Oryza sativa L.) is closely related to leaf and flower development. Coordinative regulation of leaf, pollen, and seed development in rice as a critical biological and agricultural question should be addressed. Here we identified two allelic rice mutants with narrow and semi-rolled leaves, named narrow and rolled leaf 2-1 (nrl2-1) and nrl2-2. Map-based molecular cloning revealed that NRL2 encodes a novel protein with unknown biochemical function. The mutation of NRL2 caused pleiotropic effects, including a reduction in the number of longitudinal veins, defective abaxial sclerenchymatous cell differentiation, abnormal tapetum degeneration and microspore development, and the formation of more slender seeds compared with the wild type (WT). The NRL2 protein interacted with Rolling-leaf (RL14), causing the leaves of the nrl2 mutants to have a higher cellulose content and lower lignin content than the WT, which may have been related to sclerenchymatous cell differentiation and tapetum degeneration. Thus, this gene is an essential developmental regulator controlling fundamental cellular and developmental processes, serving as a potential breeding target for high-yielding rice cultivars.

Keywords: male fertility; narrow and rolled leaf; nrl2; sclerenchymatous cell; secondary cell wall; seed size.

MeSH terms

  • Cell Wall / metabolism
  • Conserved Sequence
  • Fertility
  • Gene Expression Regulation, Plant
  • Genes, Plant*
  • Mutation / genetics
  • Organ Size
  • Oryza / anatomy & histology*
  • Oryza / genetics*
  • Oryza / ultrastructure
  • Phenotype
  • Phenylalanine / metabolism
  • Plant Leaves / anatomy & histology*
  • Plant Leaves / genetics
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Pollen / cytology
  • Pollen / metabolism
  • Pollen / ultrastructure
  • Seeds / anatomy & histology*

Substances

  • Plant Proteins
  • Phenylalanine