Rice is highly sensitive to cold stress during reproductive developmental stages, and little is known about the mechanisms of cold responses in rice anther. Using the HiSeq™ 2000 sequencing platform, the anther transcriptome of photo thermo sensitive genic male sterile lines (PTGMS) rice Y58S and P64S (Pei’ai64S) were analyzed at the fertility sensitive stage under cold stress. Approximately 243 million clean reads were obtained from four libraries and aligned against the oryza indica genome and 1497 and 5652 differentially expressed genes (DEGs) were identified in P64S and Y58S, respectively. Both gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted for these DEGs. Functional classification of DEGs was also carried out. The DEGs common to both genotypes were mainly involved in signal transduction, metabolism, transport, and transcriptional regulation. Most of the DEGs were unique for each comparison group. We observed that there were more differentially expressed MYB (Myeloblastosis) and zinc finger family transcription factors and signal transduction components such as calmodulin/calcium dependent protein kinases in the Y58S comparison group. It was also found that ribosome-related DEGs may play key roles in cold stress signal transduction. These results presented here would be particularly useful for further studies on investigating the molecular mechanisms of rice responses to cold stress.

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Eating and cooking qualities (ECQs) of rice are important attributes due to its major influence on consumer acceptability. To better understand the molecular mechanism of the variation in ECQs, we investigated and compared the expression among different alleles of the Waxy (Wx) gene and its effect on ECQs in specialty rice cultivars. The results showed that the accumulation of amylose was positively and significantly correlated to the level of mature Wx mRNA and granule-bound starch synthase I (GBSS I) in developing rice grain at 12 day after flowering. The amount of GBSS I and its activity together are the main factors controlling amylose synthesis. Differences in eating and cooking properties among five Wx allele types were investigated in samples from 15 rice varieties. The apparent amylose content (AAC) and gel consistency (GC) were similar in each type of Wx allele. The AAC followed the order, Wx a type>Wx in type>Wx b type >Wx mq type>wx. Contrary to this, the GC showed an opposite trend compared to AAC. There was a wide variation in rapid visco analyzer (RVA) profile among five Wx allele types, while varieties sharing a specified Wx allele had basically the similar RVA profile, although there was a slight difference in some RVA parameters, peak viscosity, hot paste viscosity and cool paste viscosity.