Structure and regulation of the Asr gene family in banana

Abstract

Abscisic acid, stress, ripening proteins (ASR) are a family of plant-specific small hydrophilic proteins. Studies in various plant species have highlighted their role in increased resistance to abiotic stress, including drought, but their specific function remains unknown. As a first step toward their potential use in crop improvement, we investigated the structure and regulation of the Asr gene family in Musa species (bananas and plantains). We determined that the Musa Asr gene family contained at least four members, all of which exhibited the typical two exons, one intron structure of Asr genes and the ''ABA/WDS'' (abscisic acid/ water deficit stress) domain characteristic of Asr genes.Phylogenetic analyses determined that the Musa Asr genes were closely related to each other, probably as the product of recent duplication events. For two of the four members, two versions corresponding to the two sub-genomes of Musa, acuminata and balbisiana were identified. Gene expression and protein analyses were performed and Asr expression could be detected in meristem cultures, root, pseudostem, leaf and cormus. In meristem cultures, mAsr1 and mAsr3 were induced by osmotic stress and wounding, while mAsr3 and mAsr4 were induced by exposure to ABA. mASR3 exhibited the most variation both in terms of amino acid sequence and expression pattern, making it the most promising candidate for further functional study and use in crop improvement.

ASR1 transcription factor and its role in metabolism

“…Members of the ASR family are present in Solanaceae, grape, maize and conifers, but surprisingly the model plant Arabidopsis thaliana lacks structural homologs. 5 The organization of the family varies among the species: 5 paralogs have been described in tomato, 6,7 9 in maize, 8 3 in potato, 9 6 in rice, 10 4 in banana 11 and one in melon. 12 In general, the ASR proteins are small (molecular mass of tomato ASR1 is 13 kDa) and, specifically, tomato ASR1 is intrinsically unstructured.…”

“…Among others, this increase occurs in tobacco and tomato by osmotic and drought stress; 4,16,[20][21][22] in rice by drought, saline and osmotic stress; 10,23,24,25 and in plantain and banana by osmotic and biotic stress. 11,26,27 Only a few physiological studies with transgenic tomato, 28 tobacco, 22 maize, 29 and rice 18 plants have proved the involvement of ASR1 in stress tolerance.…”

The ZmASR1 Protein Influences Branched-Chain Amino Acid Biosynthesis and Maintains Kernel Yield in Maize under Water-Limited Conditions

“…Moreover, ABA induces some ASR genes in a range of plant species, including tomato, tobacco, grape, banana, sugarcane (Saccharum officinarum), and rice (Rossi et al, 1998;Sugiharto et al, 2002;Cakir et al, 2003;Takasaki et al, 2008;Henry et al, 2011). Sugars such as Glc also exhibit interactions with ABA in controlling seedling development (Rolland et al, 2006), and grape and tomato ASR proteins may be involved in Glc metabolism (Cakir et al, 2003;Frankel et al, 2007).…”

“…Since their discovery more than a decade ago, they have been described as accumulating to high levels during plant developmental processes, such as fruit ripening, pollen maturation, and Glc metabolism (Iusem et al, 1993;Wang et al, 1998;Cakir et al, 2003;Frankel et al, 2007;Yang et al, 2008), and in response to diverse stresses, including water deficit, salt, cold, limited light, and, lately, pathogen attack (Schneider et al, 1997;Riccardi et al, 1998;Vaidyanathan et al, 1999;Huang et al, 2000;Maskin et al, 2001;Kalifa et al, 2004b;Liu et al, 2010;Philippe et al, 2010;Henry et al, 2011). Nevertheless, it is noteworthy that their exact function remains enigmatic.…”

Improved cryopreservation method for the long-term conservation of the world potato germplasm collection

“…Authors attribute these differences to the different culture techniques utilized for applying the sucrose treatment. In this study cultures were subjected to the cold and sugar stress immediately after stem cuttings are excised while Folgado's method applied the sucrose treatment in plantlets on 1 week cultures without an excision phase thus preventing an additional cutting stress that can result in the production of stress proteins such as ASRs (Henry et al 2011). Cold-acclimation is used in frost tolerance studies and sugar treatments have been applied in drought tolerance research.…”