Rolling Leaf 2 Controls Leaf Rolling by Regulating Adaxial-Side Bulliform Cell Number and Size in Rice.

Area of Science:

• Plant Biology
• Genetics
• Agronomy

Background:

• Leaves are crucial for photosynthesis, and ideal plant architecture, including moderate leaf rolling, can enhance rice yields.
• Understanding the genetic basis of leaf morphology is key to improving crop architecture.

Purpose of the Study:

• To identify and characterize a novel rice mutant with a stable inherited rolled leaf phenotype.
• To elucidate the genetic and molecular mechanisms underlying leaf rolling in rice.

Main Methods:

• Ethyl methanesulfonate (EMS) mutagenesis was used to generate the mutant.
• Genetic analysis, map-based cloning, and transcriptome sequencing were employed.
• Semi-thin sections were used to examine leaf cellular structure.

Main Results:

• A recessive nuclear gene mutant, rll2, was identified with significantly altered leaf morphology, including shorter and narrower leaves and increased bulliform cell size and number.
• Map-based cloning revealed that the RLL2 gene encodes a plant-specific calpain-like cysteine proteinase.
• Transcriptome analysis identified 104 differentially expressed genes, including transcription factors, in the rll2 mutant.

Conclusions:

• The RLL2 gene plays a significant role in regulating rice leaf rolling, primarily by influencing bulliform cell development.
• The rll2 mutant provides a valuable resource for understanding leaf development and for breeding rice varieties with improved plant architecture and yield potential.