The grapevine guard cell-related VvMYB60 transcription factor is involved in the regulation of stomatal activity and is differentially expressed in response to ABA and osmotic stress

- Background: Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which induces the rapid closure of stomatal pores to prevent water loss. This event is trigged by a series of signals produced inside guard cells which finally reduce their turgor. Many of these events are tightly regulated at the transcriptional level, including the control exerted by MYB proteins. In a previous study, while identifying the grapevine R2R3 MYB family, two closely related genes, VvMYB30 and VvMYB60 were found with high similarity to AtMYB60, an Arabidopsis guard cell-related drought responsive gene. - Results: Promoter-GUS transcriptional fusion assays showed that expression of VvMYB60 was restricted to stomatal guard cells and was attenuated in response to ABA. Unlike VvMYB30, VvMYB60 was able to complement the loss-of-function atmyb60-1 mutant, indicating that VvMYB60 is the only true ortholog of AtMYB60 in the grape genome. In addition, VvMYB60 was differentially regulated during development of grape organs and in response to ABA and drought-related stress conditions. - Conclusions: These results show that VvMYB60 modulates physiological responses in guard cells, leading to the possibility of engineering stomatal conductance in grapevine, reducing water loss and helping this species to tolerate drought under extreme climatic conditions

Gene trap-based identification of a guard cell promoter in Arabidopsis

Preserving crop yield under drought stress is a major challenge for modern agriculture. To cope with the detrimental effects of water scarcity on crop productivity it is important to develop new plants with a more sustainable use of water and capable of higher performance under stress conditions. Transpiration through stomatal pores accounts for over 90% of water loss in land plants. Recent studies have increased our understanding of the networks that control stomatal activity and have led to practical approaches for enhancing drought tolerance. Genetic engineering of target genes in stomata requires effective expression systems, including suitable promoters, because constitutive promoters (i.e., CaMV35S) are not always functional or can have negative effects on plant growth and productivity. Here we describe the identification of the CYP86A2 guard cell promoter and discuss its potential for gene expression in stomata

Caracterización de los instares larvales de Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) a cuatro temperaturas constantes.

Se caracterizó la fase de larva de Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae), considerando el ancho torácico, ancho de la cápsula cefálica y el largo de las larvas, a cuatro temperaturas constantes de 20, 25, 30 y 35 °C. La larva en el instar I, midió en promedio 1,28; 0,39 y 0,31 mm de largo, ancho torácico y ancho de la cápsula cefálica respectivamente, bajo condiciones ambientales del laboratorio a 26 °C. Los otros instares larvales a las temperaturas constantes ya señaladas, mostraron un promedio del largo que van desde 2,28–2,92 mm en el instar II; 4,18–4,82 mm en el instar III y entre 6,36–6,82 mm en el instar IV. El ancho torácico presentó valores entre 0,59–0,82 mm en el instar II; 0,96 a 1,09 mm en el instar III y en el cuarto instar desde 1,55 a 1,82 mm. El ancho de la cápsula cefálica varió entre 0,39-0,47 mm en el instar II, entre 0,58 - 0,59 mm en el instar III y 0,80–0,83 mm en el instar IV. Se observó que la temperatura no afectó el número de instares. Se generaron 3 modelos predictivos por temperatura para los instares II, III y IV, los cuales consideraron las variables ancho de la cápsula cefálica y ancho torácico a 20 y 30 °C, y solo ancho de la cápsula cefálica a 25 y 35 °C, descartándose el largo como variable discriminante

The grapevine guard cell-related VvMYB60 transcription factor is involved in the regulation of stomatal activity and is differentially expressed in response to ABA and osmotic stress

Abstract Background Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which induces the rapid closure of stomatal pores to prevent water loss. This event is trigged by a series of signals produced inside guard cells which finally reduce their turgor. Many of these events are tightly regulated at the transcriptional level, including the control exerted by MYB proteins. In a previous study, while identifying the grapevine R2R3 MYB family, two closely related genes, VvMYB30 and VvMYB60 were found with high similarity to AtMYB60, an Arabidopsis guard cell-related drought responsive gene. Results Promoter-GUS transcriptional fusion assays showed that expression of VvMYB60 was restricted to stomatal guard cells and was attenuated in response to ABA. Unlike VvMYB30, VvMYB60 was able to complement the loss-of-function atmyb60-1 mutant, indicating that VvMYB60 is the only true ortholog of AtMYB60 in the grape genome. In addition, VvMYB60 was differentially regulated during development of grape organs and in response to ABA and drought-related stress conditions. Conclusions These results show that VvMYB60 modulates physiological responses in guard cells, leading to the possibility of engineering stomatal conductance in grapevine, reducing water loss and helping this species to tolerate drought under extreme climatic conditions.</p

The grapevine guard cell-related VvMYB60 transcription factor is involved in the regulation of stomatal activity and is differentially expressed in response to ABA and osmotic stress

- Background: Under drought, plants accumulate the signaling hormone abscisic acid (ABA), which induces the rapid closure of stomatal pores to prevent water loss. This event is trigged by a series of signals produced inside guard cells which finally reduce their turgor. Many of these events are tightly regulated at the transcriptional level, including the control exerted by MYB proteins. In a previous study, while identifying the grapevine R2R3 MYB family, two closely related genes, VvMYB30 and VvMYB60 were found with high similarity to AtMYB60, an Arabidopsis guard cell-related drought responsive gene. - Results: Promoter-GUS transcriptional fusion assays showed that expression of VvMYB60 was restricted to stomatal guard cells and was attenuated in response to ABA. Unlike VvMYB30, VvMYB60 was able to complement the loss-of-function atmyb60-1 mutant, indicating that VvMYB60 is the only true ortholog of AtMYB60 in the grape genome. In addition, VvMYB60 was differentially regulated during development of grape organs and in response to ABA and drought-related stress conditions. - Conclusions: These results show that VvMYB60 modulates physiological responses in guard cells, leading to the possibility of engineering stomatal conductance in grapevine, reducing water loss and helping this species to tolerate drought under extreme climatic conditions