Identification of differentially expressed genes in sorghum (Sorghum bicolor) brown midrib mutants

Sorghum, a species able to produce a high yield of biomass and tolerate both drought and poor soil fertility, is considered to be a potential bioenergy crop candidate. The reduced lignin content characteristic of brown midrib (bmr) mutants improves the efficiency of bioethanol conversion from biomass. Suppression subtractive hybridization combined with cDNA microarray profiling was performed to characterize differential gene expression in a set of 13 bmr mutants, which accumulate significantly less lignin than the wildtype plant BTx623. Among the 153 differentially expressed genes identified, 43 were upregulated and 110 down regulated in the mutants. A semiquantitative RT–PCR analysis applied to 12 of these genes largely validated the microarray analysis data. The transcript abundance of genes encoding L-phenylalanine ammonia lyase and cinnamyl alcohol dehydrogenase was less in the mutants than in the wild type, consistent with the expectation that both enzymes are associated with lignin synthesis. However, the gene responsible for the lignin synthesis enzyme cinnamic acid 4-hydroxylase was upregulated in the mutants, indicating that the production of monolignol from L-phenylalanine may involve more than one pathway. The identity of the differentially expressed genes could be useful for breeding sorghum with improved efficiency of bioethanol conversion from lignocellulosic biomass

Screening for and Identification of an Anti-clam Vibrio Marine Bacterium from an Aquaculture Pond in the Yellow Sea

The identification and use of probiotic bacterial stains is a practical approach to protect clams grown in aquaculture farms from disease. The inhibition of the pathogenic bacterium Vibrio alginolyticus was used as a trait to select a candidate probiotic bacterial strain in this study. An ideal bacterial strain, SW-1, was isolated from seawater from a clam farm. The selected isolate SW-1 was identified based on its physiological, morphological, and biochemical characteristics and its 16S rDNA sequence. The experiments showed that strain SW-1 had a high similarity to Pseudoalteromonas piscicida and could inhibit the growth of V. alginolyticus (V.-MP-1). SW-1 also improved the survival of clams following challenge with the pathogenic V.-MP-1. The mortality of clams was 100% after infection with 10(8) CFU/mL of V. alginolyticus, whereas mortality was only 11% when clams were infected with 10(8) CFU/mL of V.-MP1 while simultaneously exposed to the same concentration of Pseudoalteromonas SW-1, indicating that Pseudoalteromonas SW-1 could be used as a probiotic to protect farmed clams, and thus reduce the effects of antibiotics on aquatic environment