PT  - JOURNAL ARTICLE
AU  - Pamela Salinas
AU  - Carlos Salinas
AU  - Rodrigo A. Contreras
AU  - Gustavo E. Zuñiga
AU  - Paul Dupree
AU  - Liliana Cardemil
TI  - Expression of a glucomannan mannosyltransferase gene (<em>GMMT</em>) from Aloe vera is induced by water deficit and abscisic acid
AID  - 10.1101/306829
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 306829
4099  - http://biorxiv.org/content/early/2018/04/23/306829.short
4100  - http://biorxiv.org/content/early/2018/04/23/306829.full
AB  - GMMT (a possible CSLA9) from Aloe vera is upregulated during water stress. Aloe vera GMMT expression is also induced by exogenous application of the plant stress hormone abscisic acid (ABA) in non-water-stressed plants.Summary In Aloe barbadensis Miller (Aloe vera), a xerophytic crassulacean acid metabolism (CAM) plant, the main polysaccharide of the gel present in the leaves is an acetylated glucomannan named acemannan. This polysaccharide is responsible for the plant succulence, helping it to retain water. In this study we determined using polysaccharide analysis by carbohydrate gel electrophoresis (PACE) that the acemannan is a glucomannan without galactose side branches. We also investigated the expression of the gene responsible for acemannan backbone synthesis, encoding a glucomannan mannosyltransferase (GMMT). It was found by in silico analyses that the GMMT gene belongs to the cellulose synthase like A type-9 (CSLA9) subfamily. Using RT-qPCR it was found that the expression of GMMT increased in Aloe vera plants subjected to water stress. This expression correlates with an increase of endogenous ABA levels, suggesting that the gene expression could be regulated by ABA. To corroborate this hypothesis, exogenous ABA was applied to non-water-stressed plants, increasing the expression of GMMT significantly 48 h after ABA treatment.