The rice FRIZZY PANICLE (FZP) locus on chromosome 7, in which an ERF and acidic domain are present, is concerned with the regulation of spikelet meristem identity and the determination of panicle architecture. Many fzp mutants drastically alter panicle morphology with higher-order rachis-branches developing successively instead of the development of floral organs in these mutants. A new mutant showing the same fzp phenotype was induced by γ-ray irradiation of seeds of a rice cultivar “Gimbozu”. Examination of this fzp-like mutant for its allelism to a known allele of fzp-1, nucleotide sequence, and panicle and agronomic characteristics clearly indicated that the allele of this fzp-like mutant is located in FZP. Because there is a previously identified allele called fzp-9, we designated this new allele as fzp-10. fzp-10 has a single nucleotide (cytosine) deletion between the ERF domain and the acidic domain, which results in a frameshift mutation and a premature stop codon, thereby altering the C-terminus of the encoded protein. The degree of higher-order branching in the panicles was significantly reduced in the fzp-10 mutant compared with that of fzp-1. Moreover, the fzp-10 mutant showed highly depressed culm and panicle lengths and panicle number, as well as delayed heading dates compared with its wild type and also with fzp-1. fzp-10 has several new characteristics, its altered nucleotide position and severity of phenotype alteration, and, therefore, could be a new gene resource to examine the function of FZP and the determination of rice panicle architecture.
水稻卷穗FZP基因位于水稻第7號(hào)染色體上，編碼一個(gè)具有ERF 和酸性結(jié)構(gòu)域的蛋白，調(diào)控著水稻穎花分生組織的特征以及決定水稻穗型。許多fzp突變體以連續(xù)的高位的穗軸分枝發(fā)育替代花器官的發(fā)育從而顯著的改變穗型。我們通過(guò)γ射線誘變水稻品種Gimbozu獲得一個(gè)與fzp表型相同的突變體，經(jīng)檢測(cè)該fzp-like突變體與已知的fzp-1突變體是等位的。通過(guò)測(cè)序以及穗型和農(nóng)藝性狀的鑒定發(fā)現(xiàn)，該fzp-like位于FZP處。由于之前有fzp-9的報(bào)道，我們因此命名該等位突變體為fzp-10，fzp-10 在ERF和酸性結(jié)構(gòu)域之間有一個(gè)堿基的缺失，導(dǎo)致移碼突變而提早產(chǎn)生終止密碼子。因此改變了編碼蛋白的C端。fzp-10 突變體穗部高位的分枝程度明顯比野生型要減少。而且fzp-10突變體的莖桿和穗的長(zhǎng)度以及穗的數(shù)目都明顯減少，且抽穗變晚。fzp-10突變體有一些新的特征；核苷酸位置變化和表型變化的嚴(yán)重程度。因此，它可作為一個(gè)新的基因資源來(lái)檢測(cè)FZP的功能以及決定水稻的穗型。