Vojta Petr, Kokáš Filip, Husičková Alexandra, Grúz Jiří, Bergougnoux Veronique, Marchetti Cintia F, Jiskrová Eva, Ježilová Eliška, Mik Václav, Ikeda Yoshihisa, Galuszka Petr
Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic; Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University in Olomouc, Hněvotínská 1333/5, 779 00 Olomouc, Czech Republic.
Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
N Biotechnol. 2016 Sep 25;33(5 Pt B):676-691. doi: 10.1016/j.nbt.2016.01.010. Epub 2016 Feb 11.
Cytokinin plant hormones have been shown to play an important role in plant response to abiotic stresses. Herein, we expand upon the findings of Pospíšilová et al. [30] regarding preparation of novel transgenic barley lines overexpressing cytokinin dehydrogenase 1 gene from Arabidopsis under the control of mild root-specific promotor of maize β-glycosidase. These lines showed drought-tolerant phenotype mainly due to alteration of root architecture and stronger lignification of root tissue. A detailed transcriptomic analysis of roots of transgenic plants subjected to revitalization after drought stress revealed attenuated response through the HvHK3 cytokinin receptor and up-regulation of two transcription factors implicated in stress responses and abscisic acid sensitivity. Increased expression of several genes involved in the phenylpropanoid pathway as well as of genes encoding arogenate dehydratase/lyase participating in phenylalanine synthesis was found in roots during revitalization. Although more precursors of lignin synthesis were present in roots after drought stress, final lignin accumulation did not change compared to that in plants grown under optimal conditions. Changes in transcriptome indicated a higher auxin turnover in transgenic roots. The same analysis in leaves revealed that genes encoding putative enzymes responsible for production of jasmonates and other volatile compounds were up-regulated. Although transgenic barley leaves showed lower chlorophyll content and down-regulation of genes encoding proteins involved in photosynthesis than did wild-type plants when cultivated under optimal conditions, they did show a tendency to return to initial photochemical activities faster than did wild-type leaves when re-watered after severe drought stress. In contrast to optimal conditions, comparative transcriptomic analysis of revitalized leaves displayed up-regulation of genes encoding enzymes and proteins involved in photosynthesis, and especially those encoded by the chloroplast genome. Taken together, our results indicate that the partial cytokinin insensitivity induced in barley overexpressing cytokinin dehydrogenase contributes to tolerance to drought stress.
细胞分裂素类植物激素已被证明在植物对非生物胁迫的响应中发挥重要作用。在此，我们扩展了波斯皮希洛娃等人[30]的研究结果，这些结果涉及在玉米β - 糖苷酶温和的根特异性启动子控制下，制备过表达拟南芥细胞分裂素脱氢酶1基因的新型转基因大麦品系。这些品系表现出耐旱表型，主要是由于根系结构的改变和根组织更强的木质化。对干旱胁迫后复壮的转基因植物根系进行的详细转录组分析表明，通过HvHK3细胞分裂素受体的响应减弱，以及与胁迫响应和脱落酸敏感性相关的两个转录因子上调。在复壮过程中，根中参与苯丙烷途径的几个基因以及参与苯丙氨酸合成的阿罗酸脱水酶/裂解酶编码基因的表达增加。尽管干旱胁迫后根中木质素合成的前体更多，但与在最佳条件下生长的植物相比，最终木质素积累没有变化。转录组的变化表明转基因根中生长素周转更高。在叶片中的相同分析表明，编码负责茉莉酸和其他挥发性化合物产生的假定酶的基因上调。尽管在最佳条件下培养时，转基因大麦叶片比野生型植物表现出更低的叶绿素含量和参与光合作用的蛋白质编码基因的下调，但在严重干旱胁迫后重新浇水时，它们确实表现出比野生型叶片更快恢复到初始光化学活性的趋势。与最佳条件相反，复壮叶片的比较转录组分析显示，参与光合作用的酶和蛋白质编码基因上调，尤其是叶绿体基因组编码的那些基因。综上所述，我们的结果表明，在过表达细胞分裂素脱氢酶的大麦中诱导的部分细胞分裂素不敏感性有助于耐旱胁迫。
