Comparative Transcriptome Analysis of Grafted Tomato with Drought Tolerance

Abstract

Grafting is a method used in agriculture to improve crop production and tolerance to biotic and abiotic stress. This technique is widely used in tomato, Solanum lycopersicum L.; however, the effects of grafting on changes in gene expression associated with stress tolerance in shoot apical meristem cells are still under-discovered. To clarify the effect of grafting, we performed a transcriptomic analysis between non-grafted and grafted tomatoes using the tomato variety Momotaro-scion and rootstock varieties, TD1, GS, and GF. Drought tolerance was significantly improved not only by a combination of compatible resistant rootstock TD1 but also by self-grafted compared to non-grafted lines. Next, we found the differences in gene expression between grafted and non-grafted plants before and during drought stress treatment. These altered genes are involved in the regulation of plant hormones, stress response, and cell proliferation. Furthermore, when comparing compatible (Momo/TD1 and Momo/Momo) and incompatible (Momo/GF) grafted lines, the incompatible line reduced gene expression associated with phytohormones but increased in wounding and starvation stress-response genes. These results conclude that grafting generates drought stress tolerance through several gene expression changes in the apical meristem.

Self-grafting-induced epigenetic changes leading to drought stress tolerance in tomato plants

“… 5 , 6 We previously found that Momotaro (Momo) homo-grafting, using the same species as a vigorous rootstock, and self-grafted, increased drought tolerance after 12 days of drought stress treatment. 7 While it was expected in homo-grafting, we observed that self-grafting also increased drought tolerance in Momo shoots. Several differentially expressed genes were found in the shoot apical meristem; however, the mechanism behind its activation is still unclear.…”

“…Recently, similar gene expression changes were found in a homo-grafted tomato with vigorous rootstock. 7 However, self-grafting through wounding could have strengthened the root system. One mechanism of wounding or mechanical stress that induces changes in plants is thigmomorphogenesis, where the signalling pathways of phytohormones are implicated and thus may trigger potential responses to stress.…”

“…The plants were then irrigated for 3 d, and those with new leaves emerging from the apical meristem, or from axillary buds due to loss of apical dominance, were counted as surviving plants. 7 Meanwhile, no surviving plants showed wilted and no growth. Shoot apexes (approximately 15 mm long) containing apical meristematic tissue were collected before stress (D0) and on day 3 (D3) during drought stress treatment in three biological replications in each group.…”

Transcriptome Analysis Reveals Key Genes Involved in the Response of Pyrus betuleafolia to Drought and High-Temperature Stress

“…Drought or high temperatures seriously affect the growth and development of crops. Plants have evolved various ways to cope with drought or high-temperature stress, including the regulation of morphology, response to cellular stress, hormone content, antioxidant content, and enzyme activity [ 1 , 15 , 19 , 23 , 24 ]. These stress responses are all based on regulation by corresponding genes.…”

Transcriptomic Profiling of Tomato Leaves Identifies Novel Transcription Factors Responding to Dehydration Stress

“…Although several transcriptome analyses have been reported to identify genes responding to dehydration stress in tomatoes [15,35], they only presented DEGs (differentially expressed genes) from the genome-wide level instead of specific groups of genes. Here, we performed genome-wide RNA sequencing of tomato leaves treated with or without dehydration, and specifically focused on differentially expressed TFs.…”