Leaf shape has long been considered to be an important agronomic trait in rice. Moderate leaf rolling can help maintain the erectness of leaves which ultimately benefits crops growth by improving light acceptance, delaying leaf senescence, and accelerating the accumulation of dry matter. Therefore, identifying mutants with moderately rolled leaves and isolating genes that control leaf rolling will be beneficial for breeding crops with the desired architecture and stress tolerance.
Researchers in Dr. CHENG Zhukuan’s group from the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, recently reported a Semi-Rolled Leaf2 (SRL2) gene which encodes a novel plant-specific protein that functions in regulating rice leaf rolling.
They described a srl2 rice mutant, which has incurved leaves due to the presence of defective sclerenchymatous cells on the abaxial side of the leaf and displays narrow leaves and reduced plant height. SRL2 appears to be ubiquitously expressed, although it is preferentially expressed in rapidly growing tissues and at specific stages of leaf development. It was mainly expressed in the vascular bundles of leaf blades, leaf sheaths, and roots, especially in their sclerenchymatous cells.
The transcriptional activities of several leaf development-related
YABBY genes were significantly altered in the
srl2 mutant, which suggested that the phenotypes of
srl2 might be related to these YABBY genes. Double mutant analysis suggested that
SRL2 and
SHALLOT-LIKE1 (
SLL1)/
ROLLED LEAF9 (
RL9) function in distinct pathways that regulate abaxial-side leaf development. Hence, SRL2 plays an important role in regulating leaf development, particularly during sclerenchymatous cell differentiation.
The in-depth characterization of a semi-rolled leaf mutant they performed in this study may be useful for breeding rice with an ideal plant architecture.
This work entitled “
Semi-Rolled Leaf2 modulates rice leaf rolling by regulating abaxial side cell differentiation” has been published in
Journal of Experimental Botany (
doi:10.1105/tpc.15.00605), with LIU Xiaofei and LI Ming as the co-first authors.
This research was financially supported by grants from the Ministry of Sciences and Technology of China (2014ZX0800939B and 2013ZX08009-003), and the National Natural Science Foundation of China (31371589).
Contact:
Dr. CHENG Zhukuan
Figure. Phenotypic characterization. (A) Two-week-old wild-type and srl2 seedlings. (B) Mature wild-type and srl2 plants. (C) Wild-type and srl2 leaves. (D) Wild-type and srl2 internodes. (E) Quantification of wild-type and srl2 internode length (mean of 15 culms ±SD). (F) Percentage of contribution of each internode to the total plant height of wild-type and srl2 plants (mean of 15 culms ±SD). I–V, first to fifth internode. (G) Leaf width of the wild type and srl2 (mean of 29 leaves ±SD). (H) LRI of the top two leaves of srl2 at the heading stage. Scale bar 2 cm (A, D), 10 cm (B), and 1cm (C). (Image by IGDB)
