Contrasting Effects of Wild Arachis Dehydrin Under Abiotic and Biotic Stresses

Abstract

Plant dehydrins (DNHs) belong to the LEA (Late Embryogenesis Abundant) protein family and are involved in responses to multiple abiotic stresses. DHNs are classified into five subclasses according to the organization of three conserved motifs (K-; Y-; and S-segments). In the present study, the DHN protein family was characterized by molecular phylogeny, exon/intron organization, protein structure, and tissue-specificity expression in eight Fabaceae species. We identified 20 DHN genes, encompassing three (Y n SK n , SK n , and K n ) subclasses sharing similar gene organization and protein structure. Two additional low conserved DHN Φ-segments specific to the legume SK n -type of proteins were also found. The in silico expression patterns of DHN genes in four legume species ( Arachis duranensis, A. ipaënsis, Glycine max , and Medicago truncatula ) revealed that their tissue-specific regulation is associated with the presence or absence of the Y-segment. Indeed, DHN genes containing a Y-segment are mainly expressed in seeds, whereas those without the Y-segment are ubiquitously expressed. Further qRT-PCR analysis revealed that, amongst stress responsive dehydrins, a SK n -type DHN gene from A. duranensis ( AdDHN1 ) showed opposite response to biotic and abiotic stress with a positive regulation under water deficit and negative regulation upon nematode infection. Furthermore, transgenic Arabidopsis lines overexpressing (OE) AdDHN1 displayed improved tolerance to multiple abiotic stresses (freezing and drought) but increased susceptibility to the biotrophic root-knot nematode (RKN) Meloidogyne incognita . This contradictory role of AdDHN1 in responses to abiotic and biotic stresses was further investigated by qRT-PCR analysis of transgenic plants using a set of stress-responsive genes involved in the abscisic acid (ABA) and jasmonic acid (JA) signaling pathways and suggested an involvement of DHN overexpression in these stress-signaling pathways.

Characterization of raffinose metabolism genes uncovers a wild Arachis galactinol synthase conferring tolerance to abiotic stresses

“…Wild-type (WT) A. thaliana plants (ecotype Columbia; Col-0) were transformed with the GV3101-pPZP-AdGolS3 Agrobacterium strain by the floral dip immersion method 32 . The eGFP-positive and hygromycin-resistant T0 transformants were grown in a controlled growth chamber (21 °C with a 12 h photoperiod and light intensity of 120 µmols.m −2 .s −1 ) to obtain transgenic AdGolS3 overexpressing (OE) lines, as described previously 22 . T1 seeds of each transgenic line obtained by self-pollination of T0 plants were germinated on hygromycin selective medium and T1 plants grown to maturity.…”

Dehydrins: an overview of current approaches and advancement

“…Similarly, the overexpression of AdDHN1, a SKn-type DHN gene from Arachis duranensis in Arabidopsis lines, was found to show enhanced tolerance to combined abiotic stress factors while increasing susceptibility to the biotrophic root node nematode. This contradictory role of AdDHN1 in response to abiotic and biotic stresses supported the idea that it was associated with the overexpression of DHN in the ABA and JA signaling pathways (Mota et al, 2019). In another study, to understand the function of CaDHN4 isolated from pepper in cold and salt tolerance and sensitivity to ABA, expression of CaDHN4 was reduced using a virusinduced gene silencing and overexpressed in Arabidopsis.…”

“…It is possible that these differences in localization are caused by an undefined sequence element (Graether and Boddington, 2014). Some DHN proteins have been observed to contain less conserved motifs (Φ segments) that are located between the K-segments and rich in glycine and polar amino acids (Campbell and Close, 1997;Graether and Boddington, 2014;Mota et al, 2019). The protein structure of DHNs can be described by the presence of the K-, Y-, and S-segments.…”

“…For example, there are only a few studies on the use of DHN genes isolated from legume species to increase stress tolerance in crops with transgenic approaches (Xie et al, 2012). In addition, identification of new editions of legumen genes, including the last gene sequence of two Arachis species (Bertioli et al, 2016), can add a new perspective to the molecular functions of DHNs in the legumens (Mota et al, 2019). These studies include both biotechnological approaches and selection of crops with high levels of DHN expression due to increased stress tolerance.…”

Three tandemly aligned LEA genes from Medicago truncatula confer differential protection to Escherichia coli against abiotic stresses

“…Considerable evidence has suggested that LEA proteins are important for tolerance of diverse organisms to abiotic stresses (Battaglia et al 2008, Hundertmark andHincha 2008). Moreover, several lines of evidence proposed involvement of LEA protein in biotic stress responses (Salleh et al 2012, Yang et al 2012, Liu et al 2013, Mota et al 2019.…”