Wang Ying, Li Na, Zhan Jiepeng, Wang Xinfa, Zhou Xue-Rong, Shi Jiaqin, Wang Hanzhong
Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Wuhan, China.
The Laboratory of Melon Crops, Zhengzhou Fruit Research Institute of the Chinese Academy of Agricultural Sciences, Zhengzhou, Henan Province, China.
Biotechnol Biofuels Bioprod. 2022 Sep 12;15(1):93. doi: 10.1186/s13068-022-02192-0.
JAZ subfamily plays crucial roles in growth and development, stress, and hormone responses in various plant species. Despite its importance, the structural and functional analyses of the JAZ subfamily in Brassica napus are still limited.
Comparing to the existence of 12 JAZ genes (AtJAZ1-AtJAZ12) in Arabidopsis, there are 28, 31, and 56 JAZ orthologues in the reference genome of B. rapa, B. oleracea, and B. napus, respectively, in accordance with the proven triplication events during the evolution of Brassicaceae. The phylogenetic analysis showed that 127 JAZ proteins from A. thaliana, B. rapa, B. oleracea, and B. napus could fall into five groups. The structure analysis of all 127 JAZs showed that these proteins have the common motifs of TIFY and Jas, indicating their conservation in Brassicaceae species. In addition, the cis-element analysis showed that the main motif types are related to phytohormones, biotic and abiotic stresses. The qRT-PCR of the representative 11 JAZ genes in B. napus demonstrated that different groups of BnJAZ individuals have distinct patterns of expression under normal conditions or treatments with distinctive abiotic stresses and phytohormones. Especially, the expression of BnJAZ52 (BnC08.JAZ1-1) was significantly repressed by abscisic acid (ABA), gibberellin (GA), indoleacetic acid (IAA), polyethylene glycol (PEG), and NaCl treatments, while induced by methyl jasmonate (MeJA), cold and waterlogging. Expression pattern analysis showed that BnC08.JAZ1-1 was mainly expressed in the vascular bundle and young flower including petal, pistil, stamen, and developing ovule, but not in the stem, leaf, and mature silique and seed. Subcellular localization showed that the protein was localized in the nucleus, in line with its orthologues in Arabidopsis. Overexpression of BnC08.JAZ1-1 in Arabidopsis resulted in enhanced seed weight, likely through regulating the expression of the downstream response genes involved in the ubiquitin-proteasome pathway and phospholipid metabolism pathway.
The systematic identification, phylogenetic, syntenic, and expression analyses of BnJAZs subfamily improve our understanding of their roles in responses to stress and phytohormone in B. napus. In addition, the preliminary functional validation of BnC08.JAZ1-1 in Arabidopsis demonstrated that this subfamily might also play a role in regulating seed weight.
JAZ亚家族在多种植物物种的生长发育、胁迫及激素应答中发挥着关键作用。尽管其重要性显著，但甘蓝型油菜中JAZ亚家族的结构和功能分析仍较为有限。
与拟南芥中存在12个JAZ基因（AtJAZ1 - AtJAZ12）相比，根据十字花科进化过程中已证实的三倍化事件，在白菜、甘蓝和甘蓝型油菜的参考基因组中分别有28、31和56个JAZ直系同源基因。系统发育分析表明，来自拟南芥、白菜、甘蓝和甘蓝型油菜的127个JAZ蛋白可分为五组。对所有127个JAZ的结构分析表明，这些蛋白具有TIFY和Jas的共同基序，表明它们在十字花科物种中具有保守性。此外，顺式作用元件分析表明，主要基序类型与植物激素、生物和非生物胁迫相关。对甘蓝型油菜中代表性的11个JAZ基因进行qRT-PCR分析表明，不同组的BnJAZ个体在正常条件下或受到不同非生物胁迫和植物激素处理时具有不同的表达模式。特别是，脱落酸（ABA）、赤霉素（GA）、吲哚乙酸（IAA）、聚乙二醇（PEG）和氯化钠处理显著抑制了BnJAZ52（BnC08.JAZ1 - 1）的表达，而茉莉酸甲酯（MeJA）、低温和渍水则诱导了其表达。表达模式分析表明，BnC08.JAZ1 - 1主要在维管束和幼花（包括花瓣、雌蕊、雄蕊和发育中的胚珠）中表达，但在茎、叶、成熟角果和种子中不表达。亚细胞定位显示该蛋白定位于细胞核，与拟南芥中的直系同源蛋白一致。在拟南芥中过表达BnC08.JAZ1 - 1导致种子重量增加，可能是通过调节参与泛素 - 蛋白酶体途径和磷脂代谢途径的下游应答基因的表达实现的。
对BnJAZs亚家族的系统鉴定、系统发育、共线性和表达分析，增进了我们对其在甘蓝型油菜胁迫和植物激素应答中作用的理解。此外，在拟南芥中对BnC08.JAZ1 - 1的初步功能验证表明，该亚家族可能也在调节种子重量中发挥作用。
