BackgroundAmino acid transporters (AATs) that transport amino acids across cellular membranes are essential for plant growth and development. To date, a genome-wide overview of the AAT gene family in rice is not yet available.Methodology/Principal FindingsIn this study, a total of 85 AAT genes were identified in rice genome and were classified into eleven distinct subfamilies based upon their sequence composition and phylogenetic relationship. A large number of OsAAT genes were expanded via gene duplication, 23 and 24 OsAAT genes were tandemly and segmentally duplicated, respectively. Comprehensive analyses were performed to investigate the expression profiles of OsAAT genes in various stages of vegetative and reproductive development by using data from EST, Microarrays, MPSS and Real-time PCR. Many OsAAT genes exhibited abundant and tissue-specific expression patterns. Moreover, 21 OsAAT genes were found to be differentially expressed under the treatments of abiotic stresses. Comparative analysis indicates that 26 AAT genes with close evolutionary relationships between rice and Arabidopsis exhibited similar expression patterns.Conclusions/SignificanceThis study will facilitate further studies on OsAAT family and provide useful clues for functional validation of OsAATs.

BackgroundPhytocyanins (PCs) are plant-specific blue copper proteins involved in electron transport, and a large number of known PCs are considered to be chimeric arabinogalactan proteins (AGPs). To date there has not been a genome-wide overview of the OsPC gene family. Therefore, as the first step and a useful strategy to elucidate the functions of OsPCs, there is an urgent need for a thorough genome-wide analysis of this gene family.Methodology/Principal FindingsIn this study, a total of 62 OsPC genes were identified through a comprehensive bioinformatics analysis of the rice (Oryza sativa L.) genome. Based on phylogeny and motif constitution, the family of OsPCs was classified into three subclasses: uclacyanin-like proteins (OsUCLs), stellacyanin-like proteins (OsSCLs) and early nodulin-like proteins (OsENODLs). Structure and glycosylation prediction indicated that 46 OsPCs were glycosylphosphatigylinositol-anchored proteins and 38 OsPCs were chimeric AGPs. Gene duplication analysis revealed that chromosomal segment and tandem duplications contributed almost equally to the expansion of this gene family, and duplication events were mostly happened in the OsUCL subfamily. The expression profiles of OsPC genes were analyzed at different stages of vegetative and reproductive development and under abiotic stresses. It revealed that a large number of OsPC genes were abundantly expressed in the various stages of development. Moreover, 17 genes were regulated under the treatments of abiotic stresses.Conclusions/SignificanceThe genome-wide identification and expression analysis of OsPC genes should facilitate research in this gene family and give new insights toward elucidating their functions in higher plants.

Polar auxin transport, mediated by influx and efflux transporters, controls many aspects of plant growth and development. The auxin influx carriers in Arabidopsis have been shown to control lateral root development and gravitropism, but little is known about these proteins in rice. This paper reports on the functional characterization of OsAUX1. Three OsAUX1 T-DNA insertion mutants and RNAi knockdown transgenic plants reduced lateral root initiation compared with wild-type (WT) plants. OsAUX1 overexpression plants exhibited increased lateral root initiation and OsAUX1 was highly expressed in lateral roots and lateral root primordia. Similarly, the auxin reporter, DR5-GUS, was expressed at lower levels in osaux1 than in the WT plants, which indicated that the auxin levels in the mutant roots had decreased. Exogenous 1-naphthylacetic acid (NAA) treatment rescued the defective phenotype in osaux1-1 plants, whereas indole-3-acetic acid (IAA) and 2,4-D could not, which suggested that OsAUX1 was a putative auxin influx carrier. The transcript levels of several auxin signalling genes and cell cycle genes significantly declined in osaux1, hinting that the regulatory role of OsAUX1 may be mediated by auxin signalling and cell cycle genes. Overall, our results indicated that OsAUX1 was involved in polar auxin transport and functioned to control auxin-mediated lateral root initiation in rice.

In eukaryotes, genetic material is packaged into a dynamic but stable nucleoprotein structure called chromatin. Post-translational modification of chromatin domains affects the expression of underlying genes and subsequently the identity of cells by conveying epigenetic information from mother to daughter cells. SWI/SNF chromatin remodelers are ATP-dependent complexes that modulate core histone protein polypeptides, incorporate variant histone species and modify nucleotides in DNA strands within the nucleosome. The present review discusses the SWI/SNF chromatin remodeler family, its classification and recent advancements. We also address the involvement of SWI/SNF remodelers in regulating vital plant growth and development processes such as meristem establishment and maintenance, cell differentiation, organ initiation, flower morphogenesis and flowering time regulation. Moreover, the role of chromatin remodelers in key phytohormone signaling pathways is also reviewed. The information provided in this review may prompt further debate and investigations aimed at understanding plant-specific epigenetic regulation mediated by chromatin remodeling under continuously varying plant growth conditions and global climate change.