Sweetpotato late embryogenesis abundant 14 (IbLEA14) gene influences lignification and increases osmotic- and salt stress-tolerance of transgenic calli

Abstract

Late embryogenesis abundant 14 (LEA14) cDNA was isolated from an EST library prepared from dehydration-treated fibrous roots of sweetpotato (Ipomoea batatas). Quantitative RT-PCR revealed a variety of different IbLEA14 expression patterns under various abiotic stress conditions. IbLEA14 expression was strongly induced by dehydration, NaCl and abscisic acid treatments in sweetpotato plants. Transgenic sweetpotato non-embryogenic calli harboring IbLEA14 overexpression or RNAi vectors under the control of CaMV 35S promoter were generated. Transgenic calli overexpressing IbLEA14 showed enhanced tolerance to drought and salt stress, whereas RNAi calli exhibited increased stress sensitivity. Under normal culture conditions, lignin contents increased in IbLEA14-overexpressing calli because of the increased expression of a variety of monolignol biosynthesis-related genes. Stress treatments elicited higher expression levels of the gene encoding cinnamyl alcohol dehydrogenase in IbLEA14-overexpressing lines than in control or RNAi lines. These results suggest that IbLEA14 might positively regulate the response to various stresses by enhancing lignification.

Molecular characterization and functional analysis by heterologous expression in E. coli under diverse abiotic stresses for OsLEA5, the atypical hydrophobic LEA protein from Oryza sativa L.

“…This is in coincidence with other group five members such as CaLEA6, IbLEA14, and PjLEA3, in which C-terminal is more hydrophilic than N-terminal (George et al 2009;Kim et al 2005;Park et al 2011). In silico predictions show that the hydrophobic regions (I, II, and III) are found in the conserved motif of OsLEA5 (Fig.…”

“…Various cellular and metabolic changes occur and various dehydration-responsive genes are induced to cope with the stress, including the synthesis of LEA proteins. Over the years, functional analysis of LEA proteins has been performed both in vivo and in vitro (Battaglia et al 2008;Bies-Ethève et al 2008;Boucher et al 2010;Dalal et al 2009;Gilles et al 2007;Hong-Bo et al 2005;Park et al 2011;Tunnacliffe and Wise 2007). There are extensive correlative data linking the expression of LEA proteins with stress resistance in plants.…”

“…In this paper, we demonstrated that the overexpression of OsLEA5 protein could increase the tolerance of E. coli recombinants to diverse stresses: high salinity, hyperosmotic, freezing, heat, and UV radiation; and protected LDH against the inactivation induced by drying, heating, and freeze-thawing. Based on the results of protective functional similarity of LEA proteins in bacteria and plant cells (Dalal et al 2009;Liu et al 2010;Park et al 2011), it is reasonable to speculate that some of the protective mechanisms might be common or similar in prokaryote and eukaryote under stress conditions.…”

“…Various environmental conditions modulate the expression of this set of proteins in different plant species (George et al 2009;Hundertmark and Hincha 2008;Park et al 2011;Su et al 2011;Tunnacliffe and Wise 2007). The group 5C LEA genes might contain ABRE (ABA responsive element) or DRE/CRT/LTRE (drought responsive/C-repeat/low-temperature response) element, which binds to the DREB/CBF or bZIP transcription factors, thus causing expression of these genes induced by various abiotic stress conditions (Hundertmark and Hincha 2008;Park et al 2011). The available information suggests that their transcripts accumulate during the late stage of seed development and in response to drought, salinity, cold, UV light, wounding, and oxidative stress (George et al 2009;Su et al 2011).…”

Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance

“…Transgenic Arabidopsis plants overexpressing NtLEA7-3 are much more resistant to cold, drought, and salt stresses [12]. In addition, other LEA proteins, such as PsLEAM from pea, IbLEA14 from sweet potato, D-19 from cotton and Em from wheat, also enhance abiotic stress tolerance [6,[13][14][15].…”