美国冷泉港实验室的David Jackson及其同事鉴定出一个在控制玉米植株发育中发挥关键作用的基因。研究人员发现，名为spi1的基因（稀疏花序）参与了玉米植物生长素的合成。众所周知，生长素可以控制植物器官发育和顶端优势。
科学家们发现，spi1的表达沉默会导致植物器官发育迟缓、有缺陷。植物器官初期被称为分生组织，是一种类似于动物体内干细胞的未分化细胞。据了解，分生组织产生于各种细胞合成生长素的相互作用以及它们之间的活动。
“我们的研究表明，玉米中的spi1在生长素合成中起主导作用，在植物科学家所称的花序发育中也至关重要--种子植物借助这一过程中的发芽来支持植物的开花，” Jackson说。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS September 17, 2008, doi: 10.1073/pnas.0805596105
sparse inflorescence1 encodes a monocot-specific YUCCA-like gene required for vegetative and reproductive development in maize
Andrea Gallavotti*,?,?, Solmaz Barazesh?,§, Simon Malcomber?, Darren Hall*, David Jackson?, Robert J. Schmidt*, and Paula McSteen
The plant growth hormone auxin plays a critical role in the initiation of lateral organs and meristems. Here, we identify and characterize a mutant, sparse inflorescence1 (spi1), which has defects in the initiation of axillary meristems and lateral organs during vegetative and inflorescence development in maize. Positional cloning shows that spi1 encodes a flavin monooxygenase similar to theYUCCA (YUC) genes of Arabidopsis, which are involved in local auxin biosynthesis in various plant tissues. In Arabidopsis, loss of function of single members of theYUC family has no obvious effect, but in maize the mutation of a single yuc locus causes severe developmental defects. Phylogenetic analysis of the different members of the YUC family in moss, monocot, and eudicot species shows that there have been independent expansions of the family in monocots and eudicots.spi1 belongs to a monocot-specific clade, within which the role of individual YUCgenes has diversified. These observations, together with expression and functional data, suggest that spi1 has evolved a dominant role in auxin biosynthesis that is essential for normal maize inflorescence development. Analysis of the interaction between spi1 and genes regulating auxin transport indicate that auxin transport and biosynthesis function synergistically to regulate the formation of axillary meristems and lateral organs in maize.
