Grain width 2 (GW2) and its interacting proteins regulate seed development in rice (Oryza sativa L.).

Background: Seed size has been extensively studied in crop plants, as it determines crop yield. However, the mechanism of seed development remains elusive. In this study, we explored the mechanism of seed development in rice (Oryza sativa L.

GW2 Functions as an E3 Ubiquitin Ligase for Rice Expansin-Like 1.

Seed size is one of the most important traits determining the yield of cereal crops. Many studies have been performed to uncover the mechanism of seed development. However, much remains to be understood, especially at the molecular level, although several genes involved in seed size have been identified.

The expression patterns of AtBSMT1 and AtSAGT1 encoding a salicylic acid (SA) methyltransferase and a SA glucosyltransferase, respectively, in Arabidopsis plants with altered defense responses.

We reported previously that overexpression of a salicylic acid (SA) methyltransferase1 gene from rice (OsBSMT1) or a SA glucosyltransferase1 gene from Arabidopsis thaliana (AtSAGT1) leads to increased susceptibility to Pseudomonas syringae due to reduced SA levels. To further examine their roles in the defense responses, we assayed the transcript levels of AtBSMT1 or AtSAGT1 in plants with altered levels of SA and/or other defense components. These data showed that AtSAGT1 expression is regulated partially by SA, or non-expressor of pathogenesis related protein1, whereas AtBSMT1 expression was induced in SA-deficient mutant plants.

Methyl jasmonate reduces grain yield by mediating stress signals to alter spikelet development in rice.

Jasmonic acid (JA) is involved in plant development and the defense response. Transgenic overexpression of the Arabidopsis (Arabidopsis thaliana) jasmonic acid carboxyl methyltransferase gene (AtJMT) linked to the Ubi1 promoter increased levels of methyl jasmonate (MeJA) by 6-fold in young panicles. Grain yield was greatly reduced in Ubi1:AtJMT plants due to a lower numbers of spikelets and lower filling rates than were observed for nontransgenic (NT) controls.

An advanced method for the determination of carboxyl methyl esterase activity using gas chromatography-chemical ionization-mass spectrometry.

We developed a quantitative method for the determination of methyl esterase activity, analyzing substrate specificity against three major signal molecules, jasmonic acid methyl ester (MeJA), salicylic acid methyl ester (MeSA), and indole-3-acetic acid methyl ester (MeIAA). We used a silylation reagent for chemical derivatization and used gas chromatography (GC)-mass spectroscopy in analyses, for high precision. To test this method, an Arabidopsis esterase gene, AtME8, was expressed in Escherichia coli, and then the kinetic parameters of the recombinant enzyme were determined for three substrates.

Overexpression of AtSGT1, an Arabidopsis salicylic acid glucosyltransferase, leads to increased susceptibility to Pseudomonas syringae.

We reported previously that a recombinant salicylic acid (SA) glucosyltransferase1 (AtSGT1) from Arabidopsis thaliana catalyzes the formation of both SA 2-O-beta-D-glucoside (SAG) and the glucose ester of SA (SGE). Here, transgenic Arabidopsis plants overexpressing AtSGT1 have been constructed, and their phenotypes analyzed. Compared to wild-type plants, transgenic plants showed an increased susceptibility to Pseudomonas syringae and reduced the accumulation levels of both free SA and its glucosylated forms (SAG and SGE).

Overexpression of AtMYB44 enhances stomatal closure to confer abiotic stress tolerance in transgenic Arabidopsis.

AtMYB44 belongs to the R2R3 MYB subgroup 22 transcription factor family in Arabidopsis (Arabidopsis thaliana). Treatment with abscisic acid (ABA) induced AtMYB44 transcript accumulation within 30 min. The gene was also activated under various abiotic stresses, such as dehydration, low temperature, and salinity.

Overexpression of salicylic acid carboxyl methyltransferase reduces salicylic acid-mediated pathogen resistance in Arabidopsis thaliana.

We cloned a salicylic acid/benzoic acid carboxyl methyltransferase gene, OsBSMT1, from Oryza sativa. A recombinant OsBSMT1 protein obtained by expressing the gene in Escherichia coli exhibited carboxyl methyltransferase activity in reactions with salicylic acid (SA), benzoic acid (BA), and de-S-methyl benzo(1,2,3)thiadiazole-7-carbothioic acid (dSM-BTH), producing methyl salicylate (MeSA), methyl benzoate (MeBA), and methyl dSM-BTH (MeBTH), respectively. Compared to wild-type plants, transgenic Arabidopsis overexpressing OsBSMT1 accumulated considerably higher levels of MeSA and MeBA, some of which were vaporized into the environment.