Os01g0907900

PLA2 encodes MEI2-like RNA binding protein that is likely to be a rice orthologue of te1.The primary function of PLA2resides in regulating leaf maturation, which in turn plays a major role in regulating plastochron in rice.

Annotated Information

Function

Taken together, our results indicated that the patatin-like PLA2 might play a significant role in the formation of vascular bundles, and that the dep3 mutant may provide another EP resource for rice breeding programs.

Phospholipase A(2)s (PLA(2)s) constitute a large superfamily of enzymes whose products are important for a multitude of signal transduction processes, lipid mediator release, lipid metabolism, development, plant stress responses, and host defense.

CSL1 may represent a novel gene, which functions downstream of PLA1 and/or PLA2, or alternatively functions in a separate pathway, involved in the regulation of leaf initiation and developmental transition via plant hormones or other mobile signals.

Mutants with abnormal leaf developmental patterns not only provide a great insight into understanding the regulatory mechanism of plant architecture, but also enrich the ways to its modification by which crop yield could be improved.

Instead, it produced a leafy panicle, in which all primary rachis-branches were converted to vegetative shoots.

These results indicate that both PLA1 and PLA2 act downstream of the GA signal transduction pathway to regulate leaf development.

Architecture of the rice inflorescence, which is determined mainly by the morphology, number and length of primary and secondary inflorescence branches, is an important agronomical trait.

Detailed analyses indicate that the primary function of PLA2 resides in regulating leaf maturation, which in turn plays a major role in regulating plastochron in rice..

Expression

PLA2 encodes MEI2-like RNA binding protein that is likely to be a rice orthologue of te1. However， despite their similarity, pla2 and te1 show distinct phenotypes, suggesting that differences in the activities of the normal genes may be partly responsible for differences between the shoot architectures of rice and maize. To gain more insight into the biological function of PLA2, we examined the PLA2 expression in detail. We first examined PLA2 expression by RT-PCR analysis. RNA was isolated from 3-weekold vegetative shoot apices, the inflorescence apex, the leaf blade, the leaf sheath, and the root. PLA2 was strongly expressed in shoot apex and inflorescence apex and intermediately in root, while low expression was detected in leaf blade and leaf sheath (see Supplemental Figure 6 online).To obtain more detailed information on the spatial pattern of PLA2 expression, we performed in situ hybridization experiments.By this method, PLA2 expression was seen throughout the life cycle. In the embryo, transcripts were detected in leaf primordia, vascular bundles, and the radicle (Figure 6A). In the vegetative phase, PLA2 was expressed in crown root apices(Figure 6B) and shoot apices (Figures 6C to 6F). Although Paquet et al. (2005) reported that PLA2/Ostel1/OML1 was expressed in shoot apices but not in roots and leaves, we detected obvious expression in roots, though no mutant phenotypes were apparent in this organ. In the shoot apex, PLA2 expression was first detected in the entire early P1 primordium that later developed into midrib (Figure 6C) and then became extended to the marginal region (Figure 6C). In P2-P4 primordia, the expression was localized to marginal and distal regions and was then downregulated from basal midrib region (Figures 6D to 6F). In older leaves than P4, PLA2 transcripts could not be detected. Almost no or only low levels of PLA2 transcripts could be detected in the SAM (Figure 6C). In the early reproductive phase, PLA2 was expressed in bracts and several external layers of the rachis meristem (Figure 6G), suggesting that at this stage, PLA2 may regulate meristem identity directly. At the later stages, PLA2 was expressed in branch meristems, floral meristems, and floral organs (Figures 6H and 6I). In the control experiment hybridized with sense RNA probe, no hybridization signals were detected(Figure 6J)..

Phenotypes of pla2 Mutants

Plastochron and Leaf Size Rice plants normally initiate leaves from the SAM at regular intervals in 1/2 alternate phyllotaxy and, like many grasses, form several juvenile leaves in embryo before dormancy. In both the wild type and pla2, three leaves were present in mature embryos.After germination, both pla2-1 and pla2-2 showed an increased rate of leaf emergence compared with the wild type (Figures 1A and 1C). Since mature wild-type and pla2 embryos have the same number of leaf primordia, the more frequent leaf emergence indicates a shorter plastochron for subsequently formed leaves in the pla2 mutant. Given the similarity of pla2-1 and pla2-2 phenotypes, we chose to focus on pla2-1 .Plastochrons of the wild type and pla2-1 were nearly constant throughout the vegetative phase at 5.0 and 1.8 d, respectively (Figure 1C). For comparison, we examined phenotypes of pla1 mutants, which were reported previously (Itoh et al., 1998;Miyoshi et al., 2004). The plastochron of pla2 is significantly shorter than pla1 (1.8 versus 2.3). Furthermore, in contrast with pla1, in which the angle between the blade and sheath is increased for all leaves, the third leaf of pla2 appears erect due to an irregular blade-sheath boundary (see Supplemental Figure 1 online). The transition of vegetative to reproductive phase was also delayed in pla2-1 and pla2-2. Together with an extended vegetative period, pla2 produced threefold as many leaves as the wild type (49 versus 16 leaves). Assuming that this increase reflects loss of normal PLA2 function, these results suggest that the PLA2 gene normally acts to inhibit leaf initiation. In addition to a shortened plastochron, pla2 plants exhibited significantly smaller leaves than the wild type with respect to the length of blade and sheath and also the width of leaf blade(Figure 1B; see Supplemental Figures 2A to 2C online). As the size of epidermal cells of the third leaf in pla2 was almost comparable to that in the wild type, this size reduction was exclusively due to the reduction in the number of cells (see Supplemental Figure 3 online). The possibility of a causal relationship between leaf size and plastochron is reinforced by the phenotype of pla1, which also shows reduced leaf size and plastochron but not as severe as seen for pla2 (Figure 1B; see Supplemental Figures 2A to 2C online). Thus, there exists a positive correlation between plastochron and leaf size in the wild type, pla1, and pla2.

Evolution

With respect to plastochron, several genes have been identified: PLASTOCHRON1 (PLA1) in rice (Oryza sativa; Miyoshi et al., 2004), terminal ear1 (te1) in maize (Zea mays; Veit et al., 1998), and ALTEREDMERISTEM PROGRAM1 (AMP1), PHYTOCHROME B (PHYB), and SERRATE (SE) in Arabidopsis thaliana (Reed et al., 1993;Helliwell et al., 2001; Prigge andWagner, 2001). pla1, te1, and amp1 show shorter plastochron. By contrast, phyB and se show longer plastochron than the wild type. With each of these genes encoding a distinct class of protein and showing distinct loss-offunction phenotypes, the regulation of plastochron appears complex.

Labs working on this gene

1Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan 2National Institute of Genetics, Mishima 411-8540, Japan 3AgResearch, Private Bag 11008, Palmerston North, New Zealand

References

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Structured Information

Gene Name	Os01g0907900
Description	Similar to Terminal ear1
Version	NM_001051674.1 GI:115441718 GeneID:4324983
Length	3557 bp
Definition	Oryza sativa Japonica Group Os01g0907900, complete gene.
Source	Oryza sativa Japonica Group ORGANISM Oryza sativa Japonica Group Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliophyta; Liliopsida; Poales; Poaceae; BEP clade; Ehrhartoideae; Oryzeae; Oryza.
Chromosome	Chromosome 1
Location	Chromosome 1:41279485..41283041
Sequence Coding Region	41279485..41280220,41280332..41280500,41280573..41281076,41281207..41281335,41282437..41282578 ,41282670..41283041
Expression	GEO Profiles:Os01g0907900
Genome Context	<gbrowseImage1> name=NC_008394:41279485..41283041 source=RiceChromosome01 preset=GeneLocation </gbrowseImage1>
Gene Structure	<gbrowseImage2> name=NC_008394:41279485..41283041 source=RiceChromosome01 preset=GeneLocation </gbrowseImage2>
Coding Sequence	<cdnaseq>atggaggaaggaggtgggagtggcgtgggtgggatgcagggagcggcgtcgaatcttctggacgccggagctcaggcgttctaccctgccgtcggcgcgccgttcccgttccagcagcttccgcaccagctgtactgcccgcagccgccgccgccgccgtaccaggtcatgccggtgccgccgccgccgccgccggtgggcttgcctgtaccgccgctgccggcgacgatggcgccgcagccgggctactgcgtgccggcggccgcgacggtggtggacggtccggccagccgcgccgtcgtgctgagcctggtgccgccgcacgcgccggaggacgagatcgcccgcgcgatggctccgttcggtgcggtgcgcgccgtggacgcgtcggcggtggcgtccgagggcgtcgcgaccgtctacttcttcgatctccgctccgccgagcacgccgtcacgggggtccgcgagcagcacatccggcagcagtgccggctcggccagctctacgccgccgccgccgccgccgccgcctcgtccccgacctggcccccgccggcgtgggactggccccacgacgacaaccgcgggctcgtcctcggccaggccgtctgggcccacttcgccgccgcctccaccgtccccgacgacggcgccagccgcggctccctcgtcgtgctcaattccctccccgccatgtccgtgttcgaactccgcgaaatcttccaagcatacggtgacgtgaaggacgtgagggagtcggcgctgcggccgagcaacaagttcgtcgagttcttcgacacgcgcgacgccgaccgcgcgctccacgagctcaacggcaaggagctcttcggccgccgcctcgtcgtcgagtacacgcgcccttccctccccggcccacgcaggcgcgggcacgtgtcgcaccagcccttggccccgacgccgccgaggctgcaggcggcttggcggccggcgccggcgccgtcgcagtctgcgcagccgtcgtcgtctggctccggcaaggcgagggaaggcgtggtgcttctgcgcaggagctccgggaaaggtagctcgggtagccagtccaagggcggtggcaatgctggccacgagcggaagagcaagggcggcaagagcgccgcggcggcgtgttcgacggcggcttcagcatcgtcgtctaccgcaacggcgcccagcaagcaaagccagaaaggcggcggcggcggcggcggccgtggcgggagctggagaggccagaagagcgggtgggaggctcgcttcctgttcaaagaacccgaggccgcggccgccgccgccggcgacgctgccgcctccgagacgcatgagccggcgagctgcaaggacacgagaaccaccgtgatgatcaggaacatcccaaacaagtacagccagaagctgctgctcaacatgctggacaaccactgcatcctctccaaccagcagatcgaggcgagctgcgaagacgaagcccagccattctcctcctacgatttcctctacctccccatagatttcaacaacaagtgcaacgtgggctatggcttcgtcaacctcacctcgccggaggctgccgtgcggctgtacaaggcgttccacaagcaaccgtgggaggtgttcaactcgcgcaagatttgccaagtgacatacgcacgcgtgcaaggcctggacgcgctcaaggagcacttcaagaactccaagttcccgtgcgacagcgacgagtacctgcccgtggtgttctcgccgccgcgggacggcaagctgctcacggagccggtgccgctggtcggccgctcgccggcaccgtcgtcggcgtccggggcgtcgtcgccgcccaagagctgcgccgcgagcgtcgacccactcgcgcaggagctcatgacagcgccgtcttcctccggcgacggcgcctcctccgcctcctcgtccaatgcccacgccgacgaggatgacgtccatggcgaaaccggtggtgaccgtggcgacgacgcggggctcgatctggagctacagcgcctaggctacactgactag</cdnaseq>
Protein Sequence	<aaseq>MEEGGGSGVGGMQGAASNLLDAGAQAFYPAVGAPFPFQQLPHQL YCPQPPPPPYQVMPVPPPPPPVGLPVPPLPATMAPQPGYCVPAAATVVDGPASRAVVL SLVPPHAPEDEIARAMAPFGAVRAVDASAVASEGVATVYFFDLRSAEHAVTGVREQHI RQQCRLGQLYAAAAAAAASSPTWPPPAWDWPHDDNRGLVLGQAVWAHFAAASTVPDDG ASRGSLVVLNSLPAMSVFELREIFQAYGDVKDVRESALRPSNKFVEFFDTRDADRALH ELNGKELFGRRLVVEYTRPSLPGPRRRGHVSHQPLAPTPPRLQAAWRPAPAPSQSAQP SSSGSGKAREGVVLLRRSSGKGSSGSQSKGGGNAGHERKSKGGKSAAAACSTAASASS STATAPSKQSQKGGGGGGGRGGSWRGQKSGWEARFLFKEPEAAAAAAGDAAASETHEP ASCKDTRTTVMIRNIPNKYSQKLLLNMLDNHCILSNQQIEASCEDEAQPFSSYDFLYL PIDFNNKCNVGYGFVNLTSPEAAVRLYKAFHKQPWEVFNSRKICQVTYARVQGLDALK EHFKNSKFPCDSDEYLPVVFSPPRDGKLLTEPVPLVGRSPAPSSASGASSPPKSCAAS VDPLAQELMTAPSSSGDGASSASSSNAHADEDDVHGETGGDRGDDAGLDLELQRLGYT D</aaseq>
Gene Sequence	<dnaseqindica>1..736#848..1016#1089..1592#1723..1851#2953..3094#3186..3557#atggaggaaggaggtgggagtggcgtgggtgggatgcagggagcggcgtcgaatcttctggacgccggagctcaggcgttctaccctgccgtcggcgcgccgttcccgttccagcagcttccgcaccagctgtactgcccgcagccgccgccgccgccgtaccaggtcatgccggtgccgccgccgccgccgccggtgggcttgcctgtaccgccgctgccggcgacgatggcgccgcagccgggctactgcgtgccggcggccgcgacggtggtggacggtccggccagccgcgccgtcgtgctgagcctggtgccgccgcacgcgccggaggacgagatcgcccgcgcgatggctccgttcggtgcggtgcgcgccgtggacgcgtcggcggtggcgtccgagggcgtcgcgaccgtctacttcttcgatctccgctccgccgagcacgccgtcacgggggtccgcgagcagcacatccggcagcagtgccggctcggccagctctacgccgccgccgccgccgccgccgcctcgtccccgacctggcccccgccggcgtgggactggccccacgacgacaaccgcgggctcgtcctcggccaggccgtctgggcccacttcgccgccgcctccaccgtccccgacgacggcgccagccgcggctccctcgtcgtgctcaattccctccccgccatgtccgtgttcgaactccgcgaaatcttccaagcatacggtacatacaccaccaccgcacgctttcttccgcgaattcctccatgtttcgcttcttgtgtttccaaccaattcattctcttggtcgggtcgcctcgtcgtgtgtttgcaggtgacgtgaaggacgtgagggagtcggcgctgcggccgagcaacaagttcgtcgagttcttcgacacgcgcgacgccgaccgcgcgctccacgagctcaacggcaaggagctcttcggccgccgcctcgtcgtcgagtacacgcgcccttccctccccggcccacgcaggtaaaagaattcaccgtcgtgttaattcccatcgaaaacgcacggtaaaactaatttggctgtggttggcaggcgcgggcacgtgtcgcaccagcccttggccccgacgccgccgaggctgcaggcggcttggcggccggcgccggcgccgtcgcagtctgcgcagccgtcgtcgtctggctccggcaaggcgagggaaggcgtggtgcttctgcgcaggagctccgggaaaggtagctcgggtagccagtccaagggcggtggcaatgctggccacgagcggaagagcaagggcggcaagagcgccgcggcggcgtgttcgacggcggcttcagcatcgtcgtctaccgcaacggcgcccagcaagcaaagccagaaaggcggcggcggcggcggcggccgtggcgggagctggagaggccagaagagcgggtgggaggctcgcttcctgttcaaagaacccgaggccgcggccgccgccgccggcgacgctgccgcctccgagacgcatgagccggcgagctgcaaggacacgagaaccaccgtgatgatcaggaacatcccaaacaagtacaggtcactccgctagcttccacgttgttgacgaaatgctatatttcatgggcgccgcgagcccagaattgcctgcctcgcattgcgagcttggcactgatgcctgagcttgtcgtctgttgcttgttcgcagccagaagctgctgctcaacatgctggacaaccactgcatcctctccaaccagcagatcgaggcgagctgcgaagacgaagcccagccattctcctcctacgatttcctctacctccccatagatttcaagtgagtcagctcccgatatgctgtatttatattttatggtgcccaatgcaagaacactgcggcacacactgtccacgcccaatgacaatgacggcctccatgcttcatttccgactgagaattcagtcctagaaaactaattaattttatgattcttgaggggaattgtgcaatggaattgcattgccgtgtgaaggaaggacaaaggtatatgaaaggggcttggaaatgtactgggagatgaatgggtagttgggagctctagctgctggtagtgatgtgtgagcttgtggatcgagttatctttgggctgggtagtactagcatgttactgcactgtactgctagtctgcaacacatatggacgcctactctggtgccatggctgtaatagcccaaatggaaaggaaattggcagtccaagggagatcacaccagatccttctcgttttgatgcatcaaatccttttgttgcatgcaatcctctgatcatgagcatctgttcacatgtctacctttcttgcgcacctgcctctaggatctcctgcctgccttgctctctttcttgcttgcttgcgctgtcttgacctgcacttccatagcaaagtccaacgcaaaaaggaggggctagacgtcatggagtagcggtgaaaaggtgcatcaatgcaaaagcgttttcaattttgacatgtagtaatatatttcttttcctgagaaaaaggtatggtgaccaatgcataattaagcactttcttttcactggagtaccaacttttatctttgcacgaaccaagttgagaaaagacctatcaaatgccccaatgactagcgtgcattgtggaatcaaaaggtagctccacaacaaaaatatgatagaaatattgttgtgcaagtttatagttccccgagcttctgacttcgaaggcctcaattccaagaatatttgtgttcttgaccttgacaagtcgtttgttatcattcataactcatttttggtcacccggttctttatcgcttctctacttgttgagaagtttttaaattcaggcattaaattatcttttcggctgtgctaacctgctaaaatatgaggccatgcagcaacaagtgcaacgtgggctatggcttcgtcaacctcacctcgccggaggctgccgtgcggctgtacaaggcgttccacaagcaaccgtgggaggtgttcaactcgcgcaagatttgccaagtgacatacgcacgcgtgcaagtacgagcgccgttaaatctctcccaattgtgctgataaatctagaccgatcatcatgtgtggcaagtgctaaacccgtgcatgcgcgcagggcctggacgcgctcaaggagcacttcaagaactccaagttcccgtgcgacagcgacgagtacctgcccgtggtgttctcgccgccgcgggacggcaagctgctcacggagccggtgccgctggtcggccgctcgccggcaccgtcgtcggcgtccggggcgtcgtcgccgcccaagagctgcgccgcgagcgtcgacccactcgcgcaggagctcatgacagcgccgtcttcctccggcgacggcgcctcctccgcctcctcgtccaatgcccacgccgacgaggatgacgtccatggcgaaaccggtggtgaccgtggcgacgacgcggggctcgatctggagctacagcgcctaggctacactgactag</dnaseqindica>
External Link(s)	NCBI Gene:Os01g0907900, RefSeq:Os01g0907900