ALK,the Key Gene for Gelatinization Temperature,is a Modifier Gene for Gel Consistency in Rice

Gelatinization temperature（GT） is an important parameter in evaluating the cooking and eating quality of rice.Indeed,the phenotype,biochemistry and inheritance of GT have been widely studied in recent times.Previous map-based cloning revealed that GT was controlled by ALK gene,which encodes a putative soluble starch synthase II-3.Complementation vector and RNAi vector were constructed and transformed into Nipponbare mediated by Agrobacterium.Phenotypic and molecular analyses of transgenic lines provided direct evidence for ALK as a key gene for GT.Meanwhile,amylose content,gel consistency and pasting properties were also affected in transgenic lines.Two of four nonsynonymous single nucleotide polymorphisms in coding sequence of ALK were identified as essential for GT.Based on the single nucleotide polymorphisms（SNPs）,two new sets of SNP markers combined with one cleaved amplified polymorphic sequence marker were developed for application in rice quality breeding.

Identification and functional analysis of the MOC1 interacting protein 1

Rice tillering is one of the most important agronomic traits that determine grain yields.Our previous study has demonstrated that the MONOCULM1 （MOC1） gene is a key component that controls the formation of rice tiller buds.To further elucidate the molecular mechanism of MOC1 involved in the regulation of rice tillering,we performed a yeast-two-hybrid screening to identify MOC1 interacting proteins （MIPs）.Here we reported that MIP1 interacted with MOC1 both in vitro and in vivo.The overexpression of MIP1 resulted in enhanced tillering and reduced plant height.In-depth characterization of the context of MIP1 and MOC1 would further our understanding of molecular regulatory mechanisms of rice tillering.

Identification and characterization of Mini1, a gene regulating rice shoot development

The aerial parts of higher plants are generated from the shoot apical meristem （SAM）. In this study, we isolated a small rice （Oryza sativa L.） mutant that showed premature termination of shoot development and was named mini rice 1 （mini1）. The mutant was first isolated from a japonica cultivar Zhonghua11 （ZH11） subjected to ethyl methanesulfonate （EMS） treatment. With bulked segregant analysis （BSA） and mapbased cloning method, Mini1 gene was finally fine-mapped to an interval of 48.6 kb on chromosome 9. Sequence analyses revealed a single base substitution from G to A was found in the region, which resulted in an amino acid change from Gly to Asp. The candidate gene Os09go363900 was predicted to encode a putative adhesion of calyx edges protein ACE （putative HOTHEAD precursor） and genetic complementation experiment confirmed the identity of Minil. Os09go36：3900 contains glucose-methanol-choline （GMC） oxidoreductase and NAD（P）-binding Rossmann-like domain, and exhibits high similarity to Arabidopsis HOTHEAD （HTH）. Expression analysis indicated Minil was highly expressed in young shoots but lowly in roots and the expression level of most genes involved in auxin biosynthesis and signal transduction were reduced in mutant. We conclude that Mini1 plays an important role in maintaining SAM activity and promoting shoot development in rice.

OsGRAS19 May Be a Novel Component Involved in the Brassinosteroid Signaling Pathway in Rice

Dear Editor, The brassinosteroid （BR） signaling pathway has been well elucidated in Arabidopsis. The identification of BR-signaling components in rice suggested that the primary pathway is conserved in both dicot and monocot plants. However,