The Transcriptional Landscape and Hub Genes Associated with Physiological Responses to Drought Stress in Pinus tabuliformis

Abstract

Drought stress has an extensive impact on regulating various physiological, metabolic, and molecular responses. In the present study, the Pinus tabuliformis transcriptome was studied to evaluate the drought-responsive genes using RNA- Sequencing approache. The results depicted that photosynthetic rate and H2O conductance started to decline under drought but recovered 24 h after re-watering; however, the intercellular CO2 concentration (Ci) increased with the onset of drought. We identified 84 drought-responsive transcription factors, 62 protein kinases, 17 transcriptional regulators, and 10 network hub genes. Additionally, we observed the expression patterns of several important gene families, including 2192 genes positively expressed in all 48 samples, and 40 genes were commonly co-expressed in all drought and recovery stages compared with the control samples. The drought-responsive transcriptome was conserved mainly between P. tabuliformis and A. thaliana, as 70% (6163) genes had a homologous in arabidopsis, out of which 52% homologous (3178 genes corresponding to 2086 genes in Arabidopsis) were also drought response genes in arabidopsis. The collaborative network exhibited 10 core hub genes integrating with ABA-dependent and independent pathways closely conserved with the ABA signaling pathway in the transcription factors module. PtNCED3 from the ABA family genes had shown significantly different expression patterns under control, mild, prolonged drought, and recovery stages. We found the expression pattern was considerably increased with the prolonged drought condition. PtNCED3 highly expressed in all drought-tested samples; more interestingly, expression pattern was higher under mild and prolonged drought. PtNCED3 is reported as one of the important regulating enzymes in ABA synthesis. The continuous accumulation of ABA in leaves increased resistance against drought was due to accumulation of PtNCED3 under drought stress in the pine needles.

An ethylene-induced NAC transcription factor acts as a multiple abiotic stress responsor in conifer

“…All four abiotic stress-induced TFs show a similar response profile to these stress conditions; however, compared with other ASIGs, PtNAC3 showed a more sensitive and vigorous expression response, indicating that it probably acts as a core transcription activator in abiotic stress response. The result showed that PtNAC3 was up-regulated under 4°C, 10°C, 30°C, 40°C temperatures compared with 20°C, and induced by 8 days of moderate drought treatment and slightly up-regulated for 23 days of progressive drought treatment, while its expression level was recovered to control level after rewatering one day [ 16 ]. We found that the response of these genes should be a very rapid process.…”

“…For temperature treatment, two-month-old P. tabuliformis seedlings were transformed to a 4°C, 10°C, 20°C, 30°C, and 40°C climate chamber for 8 hours during the light. Drought treatment raw data was from Tariq Pervaiz's study [ 16 ]; each treatment mentioned above has six repeats. For salt and osmotic treatment, P. tabuliformis seedlings were irrigated daily with 2 M NaCl or 300 mM mannitol for 3 days; UV treatment raw data was from Xu J's study [ 10 ].…”

“…For conifers, the ability to respond to abiotic stress not only predetermined potential distribution but also the length of the life-span. There was much evidence to prove conifers have a stronger ability against unfavorable environmental conditions [ 10 , 16 , 19 ]. Interestingly, the whole genome-wide analysis of Pinus tabuliformis ( P. tabuliformis ) found C-repeat/DREB binding factors (CBFs), which played an important role in abiotic stress in angiosperm, were lacking in conifer [ 19 ], indicating they probably have a different abiotic stress response pathway in conifer.…”

MicroRNA and cDNA-Microarray as Potential Targets against Abiotic Stress Response in Plants: Advances and Prospects

“…Abiotic stresses have an extensive impact on various physiological, molecular, and metabolic responses. Much progress has been made in unravelling the complex stress response mechanisms, particularly in identifying stressresponsive genes with the help of biotechnological tools [1,2]. MicroRNAs (miRNAs), play a critical role in post-transcriptional regulation through base-pairing with other miRNA targets, including transcription factors (TFs) [1,3].…”

“…Much progress has been made in unravelling the complex stress response mechanisms, particularly in identifying stressresponsive genes with the help of biotechnological tools [1,2]. MicroRNAs (miRNAs), play a critical role in post-transcriptional regulation through base-pairing with other miRNA targets, including transcription factors (TFs) [1,3]. Understanding the role of miRNAs in abiotic stresses may be helpful in the development of innovative ways for improving plant responses against abiotic stresses.…”