TY - JOUR
T1 - The LAX1 and FRIZZY PANICLE 2 genes determine the inflorescence architecture of rice by controlling rachis-branch and spikelet development
AU - Komatsu, Mai
AU - Maekawa, Masahiko
AU - Shimamoto, Ko
AU - Kyozuka, Junko
N1 - Funding Information:
We thank Emi Kurokawa for technical assistance during in situ hybridization and sectioning. We are grateful for the donation of the OSH1 clone by Makoto Matsuoka and the lax1-1 strain by Masayuki Murai. This work was supported in part by the Japan Society for the Promotion of Science, “Research for the Future” Program, JSPS-RFTF97-R16001.
PY - 2001/3/15
Y1 - 2001/3/15
N2 - We have analyzed two mutants that exhibit altered panicle architecture in rice (Oryza sativa L.). In lax1-2, which is a new and stronger allele of the previously reported lax mutant, initiation and/or maintenance of rachis-branches, lateral spikelets, and terminal spikelets was severely prevented. In situ hybridization analysis using OSH1, a rice knotted1 (kn1) ortholog, confirmed the absence of lateral meristems in lax1-2 panicles. These defects indicate that the LAX1 gene is required for the initiation/maintenance of axillary meristems in the rice panicle. In addition to its role in forming lateral meristems, the wild-type LAX1 gene acts as a floral meristem identity gene which specifies the terminal spikelet meristem. A comparison of the defects in lax1-1 and lax1-2 plants suggested that the sensitivities to reduced LAX1 activity were not uniform among different types of meristems. In the fzp2 mutant panicle, the basic branching pattern of the panicle was indistinguishable from that of the wild type; however, specification of both terminal and lateral spikelet meristems was blocked, and sequential rounds of branching occurred at the point where the spikelet meristems are initiated in the wild-type panicle. This resulted in the generation of a panicle composed of excessive ramification of rachis-branches. The lax1-1 fzp2 double mutants exhibited a novel, basically additive, phenotype, which suggests that LAX1 and FZP2 function in genetically independent pathways.
AB - We have analyzed two mutants that exhibit altered panicle architecture in rice (Oryza sativa L.). In lax1-2, which is a new and stronger allele of the previously reported lax mutant, initiation and/or maintenance of rachis-branches, lateral spikelets, and terminal spikelets was severely prevented. In situ hybridization analysis using OSH1, a rice knotted1 (kn1) ortholog, confirmed the absence of lateral meristems in lax1-2 panicles. These defects indicate that the LAX1 gene is required for the initiation/maintenance of axillary meristems in the rice panicle. In addition to its role in forming lateral meristems, the wild-type LAX1 gene acts as a floral meristem identity gene which specifies the terminal spikelet meristem. A comparison of the defects in lax1-1 and lax1-2 plants suggested that the sensitivities to reduced LAX1 activity were not uniform among different types of meristems. In the fzp2 mutant panicle, the basic branching pattern of the panicle was indistinguishable from that of the wild type; however, specification of both terminal and lateral spikelet meristems was blocked, and sequential rounds of branching occurred at the point where the spikelet meristems are initiated in the wild-type panicle. This resulted in the generation of a panicle composed of excessive ramification of rachis-branches. The lax1-1 fzp2 double mutants exhibited a novel, basically additive, phenotype, which suggests that LAX1 and FZP2 function in genetically independent pathways.
KW - Inflorescence
KW - Meristem determinacy
KW - Meristem identity
KW - Rice
KW - Shoot branching
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U2 - 10.1006/dbio.2000.9988
DO - 10.1006/dbio.2000.9988
M3 - Article
C2 - 11237465
AN - SCOPUS:0035869628
VL - 231
SP - 364
EP - 373
JO - Developmental Biology
JF - Developmental Biology
SN - 0012-1606
IS - 2
ER -