Abstract:
Post-translation modification of proteins plays a critical role in cellular signaling
processes. In recent years, the SUMO (Small Ubiquitin-Like Modifier) class of molecules
has emerged as an influential mechanism for target protein management. SUMO
proteases play a vital role in regulating pathway flux and are therefore ideal targets for
manipulating stress-responses. In the present study, the expression of an Arabidopsis
thaliana cysteine protease (OVERLY TOLERANT TO SALT-1, OTS1) in wheat (Triticum
aestivum L.) has led to improved plant growth under water stress conditions.
Transformed wheat (pUBI-OTS1) displayed enhanced growth and delayed senescence
under water deficit when compared with untransformed Gamtoos-R genotype or plants
carrying an empty vector. Transformed pUBI-OTS1 plants also maintained a high relative
moisture content (RMC), had a higher photosynthesis rate, and also had a higher total
chlorophyll content when compared to untransformed plants or plants carrying an empty
vector. SUMOylation of total protein also increased in untransformed plants but not in the
AtOTS1 transformed plants. Our results suggest that SUMO-proteases may influence
an array of mechanisms in wheat to the advantage of the crop to be more tolerant to
water stress caused by drought. This is the first report to elucidate SUMOylation effects
in the hexaploid crop wheat (T. aestivum L.).
