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CURT1 proteins in 'Arabidopsis thaliana' have been reported to be important for inducing grana curvature. Currently, we have identified transcript encoding CURT1A from 'Oryza sativa' cv. indica through RNA-seq analysis and characterised using heterologous system in Arabidopsis. The 'OsCURT1A' gene shares 80% of its amino acid sequence with Arabidopsis 'AtCURT1A'. Phylogenetic analysis revealed that the 'OsCURT1A' is also closely related to the CURT1 proteins in other choloroplast- conatining organisms. In silico analysis of OsCURT1A promoter shows that several cis-elements related to stress are present in the 5' upstream from the coding region. Under normal conditions, there were no notable changes in the phenotype and chlorophyll a;b ratio between three Arabidopsis genotypes, which were overexpressed (35S::'OsCURT1A'), T-DNA insertional mutant line ('atcurt1a'), and Wild type (Col-0). However, overexpression of 'OsCURT1A' under salinity condition demonstrate high chlorophyll a:b compared to Col-0, whereas, the lack of atcurt1a gene in the mutant line showed reduced chlorophyll a:b ratio. These results indicate that the 'OsCURT1A' might have a function as salt-stress related gene, which may indirectly regulate the chlorophyll a:b ratio. Therefore, 'OsCURT1A' can be used as a potential candidate for salinity stress tolerance in crop improvement.

Geraniol degradation pathway has long been elucidated in microorganisms through bioconversion studies, yet weakly characterised in plants; enzyme with specific nerol-oxidising activity has not been reported. A novel cDNA encodes nerol dehydrogenase (PmNeDH) was isolated from Persicaria minor. The recombinant PmNeDH (rPmNeDH) is a homodimeric enzyme that belongs to MDR (medium-chain dehydrogenases/reductases) superfamily that catalyses the first oxidative step of geraniol degradation pathway in citral biosynthesis. Kinetic analysis revealed that rPmNeDH has a high specificity for allylic primary alcohols with backbone ≤10 carbons. rPmNeDH has ∼3 fold higher affinity towards nerol (cis-3,7-dimethyl-2,6-octadien-1-ol) than its trans-isomer, geraniol. To our knowledge, this is the first alcohol dehydrogenase with higher preference towards nerol, suggesting that nerol can be effective substrate for citral biosynthesis in P. minor. The rPmNeDH crystal structure (1.54 A) showed high similarity with enzyme structures from MDR superfamily. Structure guided mutation was conducted to describe the relationships between substrate specificity and residue substitutions in the active site. Kinetics analyses of wild-type rPmNeDH and several active site mutants demonstrated that the substrate specificity of rPmNeDH can be altered by changing any selected active site residues (Asp280, Leu294 and Ala303). Interestingly, the L294F, A303F and A303G mutants were able to revamp the substrate preference towards geraniol. Furthermore, mutant that exhibited a broader substrate range was also obtained. This study demonstrates that P. minor may have evolved to contain enzyme that optimally recognise cis-configured nerol as substrate. rPmNeDH structure provides new insights into the substrate specificity and active site plasticity in MDR superfamily.

The dataset presented in this article describes microarray experiment of Auxin-binding protein 57, Abp57-overexpressing transgenic rice. The gene expression profiles were generated using Affymetrix GeneChip® Rice (Cn) Gene 1.0 ST Arrays. Total RNA from seedlings tissue of transgenic rice and wildtype, which serve as control were used as starting materials for microarray experiment. Detailed experimental methods and data analysis were described here. The raw and normalized microarray data were deposited into Gene Expression Omnibus (GEO) under accession number GSE99055.

TylP is one of five regulatory proteins involved in the regulation of antibiotic (tylosin) production, morphological and physiological differentiation inStreptomyces fradiae. Its function is similar to those of various γ-butyrolactone receptor proteins. In this report, N-terminally His-tagged recombinant TylP protein (rTylP) was overproduced inEscherichia coliand purified to homogeneity. The rTylP protein was crystallized from a reservoir solution comprising 34%(v/v) ethylene glycol and 5%(v/v) glycerol. The protein crystals diffracted X-rays to 3.05 Å resolution and belonged to the trigonal space groupP3121, with unit-cell parametersa=b= 126.62,c= 95.63 Å.