Transcriptomic Analysis Reveals Regulatory Aspect of Drought Tolerance in Barley Spike

Background and aim: during reproductive stage, drought can lead to higher yield losses. in addition, the main supply of carbon to the developing seed are the photosynthetic organs of the spike. drought resistance of the photosynthetic organs of the barely spike (lemma, palea, and awn) is well-known characteristic. given the key role of transcription factors in the responses to drought stress, the present paper tries to find the key transcription factors pertinent to drought tolerance in barley spike. methods: in this study the microarray data of spike organs (gse17669) was acquired from the national center for biotechnology information's gene expression omnibus (www.ncbi.nlm.nih.gov/projects/geo). microarray analysis was performed using geo2r (https://www.ncbi.nlm.nih.gov/geo/geo2r/) followed by identification of transcription factor families via itak (http://itak.feilab.net/cgi-bin/itak/online_itak.cgi). the peptide sequences corresponding to the deferentially expressed probe sets were retrieved from ensemble plants (https://plants.ensembl.org/index.html). results: according to results, 620, 373, and 131 probe sets showed differential expression in awn, palea, and lemma, respectively. venn diagram depicted that 43 probe sets were common among awn, palea and lemma while 483, 221 and 33 probe sets were unique to awn, palea and lemma, respectively. moreover, 26, 14, 8 distinguished transcription factor genes belonging to various families were found in awn, palea and lemma, respectively. five transcription families were common among all awn, palea and lemma. these families included ap2/erf-erf, c2h2, garp-g2-like, myb-related, and wrky. besides, 10 transcription factor families were unique to awn and 1 transcription factor family was unique to palea. interestingly, the revealed transcription factor families from the current study such as ap2/erf, myb-related and wrky have been previously reported to be involved in drought stress responses. conclusion: finding the transcription factors in deferentially expressed probe sets yields a primary knowledge of the undiscovered regulatory aspects found in barely spike to resist drought. they may thus be used as a source of novel genes for improving drought tolerance. likewise, experimental investigations on gene function could be exploited to investigate their potential for engineering transgenic plants with improved abiotic tolerance.