Highly comparative genetic analysis for genes located on terminal region of chromosome 4 among several wild species of rice

点击翻译按钮获取中文摘要

Rhizomes of Oryza longistaminata is one of the characteristics of wild species of rice. Analysis of F2 segregation between C105204 (an IRRI's accession of O. longistaminata) and a rice cultivar showed that rhizomatous trait was controlled by a dominant gene on vhromosome 4. Further, this gene was found to be linked with lg gene.Genomic sequence of Liguless gene (Lg) located on chromosome 4, which controls ligule was revealed through PCR-based analysis based on the syntenic homology to maize Lg1. Lg gene has a polypeptide of 414 amino acids and Lg gene is composed of 3 exons.Gernomic sequences, 3635 bp of Lg gene of some liguleless mutants were analyzed. T-65 and a near isogenic line for lg with T-65's genetic background, designated T-65 lg were found to have the same sequence. However, YH lg, which was induced with NaN3 had the single base substitution, G to A, at the splice site between first intron and second exon and add one set of TC in TC repeat at second intron. Short ligule mutant, designated 85ACC152 lg-a, which was induced with EMS also had single base substitution, T to C, at the splice site between first exon and first intron. Although YH lg and 85ACC152 lg-a had very important alteration at splice site required for normal mRNA, T-65 lg which is liguless had any differences of Lg genomic sequence from T-65. This results suggested that sequence of upstream region at 5' of Lg gene in T-65 lg might be different from that of T-65.We isolated two cDNAs, OSB1 and OSB2, from cDNA library of Pl^w plant leaves, showing significant identity to the basic helix-loop-helix (bHLH) proteins found in the maize R gene family. RFLP analyses using an F2 population indicate that both genes co-segregate with the purple leaf phenotype. A transient complementation assay showed that the anthocyanin pathway is inducible by OSB1 or OSB2. These results suggest that the Pl^w allele may be complex and composed of at least two genes encoding bHLH proteins.