Overexpression of persimmon DkXTH1 enhanced tolerance to abiotic stress and delayed fruit softening in transgenic plants

Abstract

DkXTH1 promoted cell elongation and more strength to maintain structural integrity by involving in cell wall assembly, thus enhanced tolerance to abiotic stress with broader phenotype in transgenic plants. Xyloglucan endotransglucosylase/hydrolase (XTH) is thought to play a key role in cell wall modifications by cleaving and re-joining xyloglucan, and participates in the diverse physiological processes. DkXTH1 was found to peak in immature expanding persimmon fruit, and its higher expression level exhibited along with firmer fruit during storage. In the present study, transgenic Arabidopsis and tomato plants were generated with DkXTH1 constitutively expressed. Overexpression of DkXTH1 enhanced tolerance to salt, ABA and drought stresses in transgenic Arabidopsis plants with respect to root and leaf growth, and survival. Transgenic tomatoes collected at the mature green stage, presented delayed fruit softening coupled with postponed color change, a later and lower ethylene peak, and higher firmness in comparison with the wild-type tomatoes during storage. Furthermore, broader leaves and tomato fruit with larger diameter were gained in transgenic Arabidopsis and tomato, respectively. Most importantly, transgenic plants exhibited more large and irregular cells with higher density of cell wall and intercellular spaces, resulting from the overactivity of XET enzymes involving in cell wall assembly. We suggest that DkXTH1 expression resulted in cells with more strength and thickness to maintain structural integrity, and thus enhanced tolerance to abiotic stress and delayed fruit softening in transgenic plants.

Cell Wall Calcium and Hemicellulose Have a Role in the Fruit Firmness during Storage of Blueberry (Vaccinium spp.)

“…In this aspect it is very noteworthy that the experiments where tomato XTH was overexpressed [65] obtained a lower depolymerization of the xyloglucans that were correlated with a higher fruit firmness, suggesting that XTH is relevant in the maintenance of cell wall stability. Similarly, the investigators overexpressed an endotransglucosylase/xyloglucan hydrolase (XTH1) obtained from persimmons in tomato, achieving significantly reduced fruit softening [66]. Thus, and based on the information present in the literature, and in agreement with the data obtained in the present work, the metabolism of hemicelluloses, and in particular of xyloglucan, would have a great impact on the firmness of the blueberry fruits postharvest.…”

Plant Cell Walls Tackling Climate Change: Biotechnological Strategies to Improve Crop Adaptations and Photosynthesis in Response to Global Warming

“…Increased XTH transcript levels were observed in plants exposed to multiple stresses [115,119]. Recently Han et al (2017) showed that DkXTH1 is involved in salinity stress tolerance in Arabidopsis [120]. Overexpression of DkXTH1 triggered the formation of broader leaves as compared with WT plants and an increase in the rates of seed germination under high salinity [120].…”

“…Recently Han et al (2017) showed that DkXTH1 is involved in salinity stress tolerance in Arabidopsis [120]. Overexpression of DkXTH1 triggered the formation of broader leaves as compared with WT plants and an increase in the rates of seed germination under high salinity [120]. In tomato (Solanum lycopersicum), the overexpression of persimmon DkXTH1 gene caused larger cells, with higher density of CW and intercellular spaces via its involvement in CW assembly.…”

“…Overexpression of CaXTH3 has been shown to induce abnormal leaf morphology and severely wrinkled leaf shapes which improved tolerance to drought in transgenic Arabidopsis and tomato plants [121,122]. Arabidopsis plants overexpressing DkXTH1 had significantly increased levels of seed germination under drought stress as compared with WT [120]. Glycoside hydrolases (GHs) are CW-related enzymes involved in the remodeling of the CW structure by organizing cellulose-cellulose interactions controlled by xyloglucans affecting CW extensibility [174,175] to facilitate plant cell expansion, differentiation, maturation, and the repair of the damaged wall under certain stresses [176].…”

Genome-wide Identification and Expression Analysis of the Eyloglucan Endotransglucosylase/hydrolase Gene Family in Poplar

“…Under low temperature, the expression of persimmon DkXTH6 gene was inhibited, while DkXTH7 showed a high level of transcription (Han et al 2016). Overexpression of DkXTH1 enhanced the tolerance of transgenic Arabidopsis to salt, ABA and drought stress, and affected the growth and survival of roots and leaves (Han et al 2017).…”