Plants have big genomes; a rare flower from Japan has a genome that is 50 times the size of a human's. These huge genomes, and associated large genes, can make it challenging for plant scientists to introduce precise genetic changes to provide resistance to a new pest or study the fundamentals of how plants grow. One way to introduce genetic changes to large segments of DNA is called recombineering; however, recombineering isn't commonly used by plant scientists. NC State researchers have produced a new set of genetic tools to make recombineering of plant genes faster and easier. They shared their methods in a recent paper published in the journal Plant Cell. They have also made the toolset available through the Arabidopsis Biological Resource Center.
植物表皮蜡质对于减少水分蒸腾、提高耐旱性、减弱紫外光伤害以及抵抗病虫害等具有重要作用。蜡质主要由超长链脂肪酸及其衍生物（醛、醇、烷烃、酮和酯类等）组成。超长链脂肪酸分别进入酰基还原途径生成偶数碳链的伯醇和酯类，脱羰途径生成偶数碳链的醛和奇数碳链的烷烃。在拟南芥茎表皮中烷烃进一步转化为仲醇和酮，而水稻等单子叶植物的叶表皮蜡质中却不含仲醇和酮。因此，烷烃被认为是单子叶植物脱羰途径的最终产物。与此同时，奇数碳链伯醇是蜡质的组成成分，但其合成途径尚不清晰。 中国科学院植物研究所曲乐庆课题组从水稻MNU诱变突变体库中筛选获得一个叶片呈沾水表型的wax crystal-sparse leaf 5（wsl5）突变体。突变体叶片表皮蜡质中烷烃异常累积，而C29伯醇含量显著降低。通过图位克隆的方法，分离出控制该性状的WSL5基因，编码一个功能未知的细胞色素P450家族蛋白CYP96B5。研究发现，CYP96B5定位于内质网，其过量表达的转基因水稻叶表皮蜡质中烷烃含量显著降低，C29伯醇含量增加；而功能敲除突变体则呈相反表型。进一步研究发现，WSL5/CYP96B5以烷烃为底物催化产生伯醇。异源表达的WSL5与拟南芥内源烷烃链中羟化酶MAH1共同竞争烷烃底物，导致前者产物C29伯醇含量增加，后者产物仲醇和酮含量降低。WSL5与饱和烷烃共同注射烟草叶片试验进一步证明其功能。该研究首次在植物中发现烷烃末端羟化酶，阐明植物中超长奇数碳链伯醇合成的机理。 该研究结果在线发表于国际学术期刊New Phytologist。曲乐庆课题组已毕业博士研究生张犊为论文的第一作者，曲乐庆为通讯作者。该研究得到国家科技部重点研发计划和自然科学基金委项目的资助。
本发明属于植物基因工程领域，具体涉及调控甘蓝型油菜菌核病抗性的中介因子BnMED16基因及应用。本发明从甘蓝型油菜westar中分离克隆得到一种控制甘蓝型油菜菌核病的基因BnMEDIATOR16(BnMED16，该基因的核苷酸序列如SEQ ID NO：1所示；其编码的蛋白质序列如SEQ ID NO：2所示。本发明对BnMED16基因进行了功能验证。通过基因工程技术在甘蓝型油菜中提高BnMED16的表达量能够激活茉莉酸抗病信号路径，提高活性氧积累和抗病相关基因的表达，使转基因油菜叶片菌核病病斑面积减少了81.20％，植物表现为更抗菌核病，对增强甘蓝型油菜对菌核病抗性具有重要的应用前景。
[学术文献] Growth and photosynthetic responses in Brassica napus differ during stress and recovery periods when exposed to combined heat, drought and elevated CO2 进入全文
Plant Physiology and Biochemistry
This study was intended to investigate how an agronomically important crop Brassica napus will be able to cope with the combined impact of a heatwave (21/14℃ vs. 33/26℃ day/night) and drought under ambient or elevated CO2 (800 vs. 400 μmol mol−1) and to what degree their recovery will be ensured after the stress, when additional CO2 is also removed. The obtained results revealed that, in the presence of an adequate water supply, B. napus performed well under heatwave conditions. However, drought fully negated all the advantages gained from hotter climate and led to a slower and incomplete recovery of gas exchange and retarded growth after the stress, regardless mitigating the effect of elevated CO2 during the stress. The mechanism by which the elevated CO2 diminished the adverse effect of a combined heat and drought stress on photosynthetic rate at saturating light (Asat) was attributed to the improved plant water relations. However, it had little effect on the recovery of Asat. In contrast, the mechanism by which photosynthesis was more impaired under the combination of heatwave and drought, compared to single drought treatment, was attributed mainly to the faster soil drying as well as faster and sharper decrease in stomatal conductance and subsequent in Ci/Ca. Keeping in mind that photosynthesis can acclimatize by downregulation to higher CO2, the results of this study, showing a weak memory of mitigating the effect of elevated CO2, highlight a potential risk of more intense and frequent heatwaves and droughts on B. napus.
[学术文献] Genome-Wide Analysis of Phospholipase D Gene Family and Profiling of Phospholipids under Abiotic Stresses in Brassica napus 进入全文
Plant and Cell Physiology
Oil crop Brassica napus is subjected to environmental stresses such as drought, cold and salt. Phospholipase Ds (PLDs) have vital roles in regulation of plant growth, development and stress tolerance. In this study, 32 BnaPLD genes were identified and classified into six subgroups depending on the conserved protein structures. High similarity in gene and protein structures exists between BnaPLDs and AtPLDs. Gene expression analysis showed that BnaPLDα1s and BnaPLDδs had higher expression than other PLDs. BnaPLDα1 and BnaPLDδ were significantly induced by abiotic stresses including dehydration, NaCl, abscisic acid (ABA) and 4℃. Lipidomic analysis showed that the content of main membrane phospholipids decreased gradually under stresses, except phosphatidylglycerol increased under the treatment of ABA and phosphatidylethanolamine increased under 4℃. Correspondingly, their product of phosphatidic acid increased often with a transient peak at 8 h. The plant height of mutants of PLDα1 was significantly reduced. Agronomic traits such as yield, seed number, silique number and branches were significantly impaired in PLDα1 mutants. These results indicate that there is a large family of PLD genes in B. napus, especially BnaPLDα1s and BnaPLDδs may play important roles in membrane lipids remodeling and maintaining of the growth and stress tolerance of B. napus.