RNAi Expression in Cotton for Control of Herbivorous Insects.

Cultivated cotton (Gossypium hirsutum) is heavily attacked by various species of insects worldwide and breeding of new varieties resistant to pests is still a hard battle to win. RNAi technology is an important reverse genetics tool to induce gene silencing in eukaryotic organisms and produce phenotypic modifications. In cotton, RNAi was applied to investigate gene function and enhance resistance to insects and pathogens.

Expression of ABA signalling genes and ABI5 protein levels in imbibed Sorghum bicolor caryopses with contrasting dormancy and at different developmental stages.

Background And Aims: Pre-harvest sprouting susceptibility in grain sorghum (Sorghum bicolor) is related to low seed dormancy and reduced embryo sensitivity to inhibition of germination by abscisic acid (ABA). Intra-specific variability for pre-harvest sprouting might involve differential regulation of ABA signalling genes.

Methods: Sorghum genes encoding homologues for ABA signalling components from other species (ABI5, ABI4, VP1, ABI1 and PKABA1) were studied at the transcriptional and protein level (ABI5) during grain imbibition for two sorghum lines with contrasting sprouting phenotypes and in response to hormones.

Tomato leaf spatial expression of stress-induced Asr genes.

Asr1 and Asr2 are water stress-inducible genes belonging to the Asr gene family, which transcriptionally regulate a sugar transporter gene, at least in grape. Using an in situ RNA hybridization methodology, we determined that, in basal conditions, expression of Asr2 in tomato leaves is detected in the phloem tissue, particularly in companion phloem cells. When plants are exposed to water stress, Asr2 expression is contained in companion cells but expands occasionally to mesophyll cells.

Dimerization and DNA-binding of ASR1, a small hydrophilic protein abundant in plant tissues suffering from water loss.

The Asr gene family is present in Spermatophyta. Its members are generally activated under water stress. We present evidence that tomato ASR1, one of the proteins of the family, accumulates in seed during late stages of embryogenesis, a physiological process characterized by water loss.