[目的]WUSCHE-相关同源盒(WUSCHEL-related homeobox,WOX)基因家族是植物特有的转录因子家族,在植物生长发育、干细胞分化调控、逆境胁迫响应等过程中扮演重要角色.开展马铃薯WOX基因家族鉴定与功能研究,将为马铃薯遗传改良提供优良基因资源与理论依据.[方法]基于拟南芥、番茄、烟草和水稻WOX蛋白序列,利用HMMER 3.0 和BLASTP鉴定马铃薯WOX基因家族成员,使用MCScanX软件分析WOX基因家族成员在马铃薯种内及种间的共线性,并采用邻接法构建系统发育进化树.利用ExPASy、GSDS等软件分析马铃薯WOX基因家族成员理化性质、基因结构、蛋白motif、启动子区域转录因子结合位点.基于PGSC数据库中马铃薯转录组数据,分析StWOXs在不同组织和非生物胁迫下的表达模式;以可能参与离体再生过程的StWOX5 作为候选基因,利用实时荧光定量PCR技术分析该基因在具有不同离体再生能力的 4 个马铃薯品种(系)再生过程中的表达情况.[结果]鉴定得到 11 个马铃薯WOX基因家族成员,分布在 5 条染色体上,分为WUS、中间和古老共 3 个进化分支,不同分支中StWOXs基因结构、蛋白motif组成、转录因子结合位点类型和数量存在不同程度的差异.表达模式结果表明,马铃薯WOX基因家族成员参与离体再生和非生物胁迫响应,StWOX4/5/11/13在愈伤组织中特异表达,StWUS、StWOX1/3c/4/5/13在甘露醇处理下上调表达,StWOX3a/11 在NaCl处理下上调表达,StWOX4/5/13 在热胁迫中上调表达,且StWOX5 相对表达量与愈伤组织分化率呈正相关.[结论]不同马铃薯WOX基因具有潜在的功能多样性,StWOX5具有促进马铃薯离体再生分化的作用,参与了非生物胁迫反应.

花作为被子植物的繁殖器官,是植物的重要组成部分,也是研究植物进化、分类的重要依据.花器官的发育受到外部环境和内部生理等多种因素的影响,不同物种或同一物种间出现不同的性状,基因作为其中的关键因子,在整个过程中发挥着重要作用,其在花发育调控中的作用一直都是大家研究的热点.花器官的花萼、花冠、雄蕊、雌蕊、胚珠五轮结构分别受到AE花发育模型中A、B、C、D、E五类基因的调控,这些基因在花器官发育过程中形成了一个复杂的基因调控网络.各类基因的表达或沉默均会导致花器官的结构发生改变,但不同的物种之间又存在差异.本研究综述了 MADS-box、AP2/ERF基因家族相关成员AP1、AP2、AP3、PI、AG、SEP、AGL6、SHP、STK及其他基因NAP、SPL、TGA、PAN、WOX等在花器官建成中的调控作用,从分子水平解析了基因在花器官发育中的影响,为进一步深入了解基因在各植物花器官发育调控中的作用提供参考.

WUSCHEL-Related Homeobox(WOX)家族是植物特有的一类转录因子,在干细胞维持和器官形态建成等发育过程中发挥重要的调控作用.兰科珍稀名贵中药植物铁皮石斛(Dendrobium catenatum)具有独特的附生生活方式和生长发育特性,对其WOX家族基因功能探究有助于进一步了解铁皮石斛发育的保守性和特异性.本研究对铁皮石斛 WOX 家族基因(DcWOX)进行了系统进化、组织表达模式、异源表达功能检测等分析.结果显示,铁皮石斛WOX家族基因可分为 3 个进化支,具有显著差异的组织表达谱;在转基因拟南芥中,DcWOX4过表达导致植株显著矮小,叶缘羽状深裂,花期推迟 2 周;DcWOX9过表达导致植株矮化,叶缘锯齿状,开花推迟 1 周,强表型植株雌雄蕊均不育;DcWOX11 过表达导致叶缘向下卷曲;DcWOX4/9/11 过表达拟南芥叶片形态建成异常与TCP家族基因和CUC家族基因的下调以及KNOX家族基因的上调有关;花期推迟与FT、SOC1和CO等早花基因的下调有关.因此,本研究表明铁皮石斛WOX家族基因在调控植株形态建成、叶发育、开花时间和育性等方面具有重要功能,进一步拓展了对 WOX 家族基因的功能了解,为深入探讨兰科植物进化与发育的保守性和独特性提供参考.

玉米遗传转化受体主要是未成熟幼胚,经过组织培养形成胚性愈伤组织,进而分化成苗.目前,对玉米胚性愈伤组织形成的分子机理的了解还不深入.为了挖掘调控玉米胚性愈伤组织形成的基因,本研究选取玉米自交系CAL28×郑58的F3群体中不同表型的愈伤组织进行RNA-seq分析.与愈伤发生差的Ⅱ型愈伤相比,愈伤发生好的Ⅰ型愈伤中共检测到4419个差异表达基因,其中1571个基因上调,2848个基因下调.GO富集分析结果表明,差异表达基因主要富集在细胞过程、催化活性、细胞组分等通路中.KEGG富集分析表明,差异表达基因主要富集在苯丙烷生物合成途径和植物激素信号转导途径.在生长素早期响应基因中,8个AUX/IAA家族基因,如IAA23、IAA33、IAA41,和4个GH3家族基因在Ⅰ型愈伤中上调表达.差异显著基因中共有隶属56个转录因子家族的2968个转录因子,其中与愈伤形成相关的AP2、WOX和LBD转录因子家族基因中的ZmEREB53、ZmEREB206、ZmEREB 184、ZmLBD10、ZmLBD24、ZmLBD31、ZmLBD32、ZmWOX5b、ZmWOX9b 等在Ⅰ型愈伤 中的表达量显著上调,对这些靶标基因进行遗传操作有可能促进玉米愈伤组织形成.本研究发现的靶标基因具有较大的应用潜力,研究结果也为解析玉米愈伤组织形成的分子机理提供了理论参考.

Trichome formation has been extensively studied as a mechanistic model for epidermal cell differentiation and cell morphogenesis in plants.However,the genetic and molecular mechanisms underlying trichome formation (i.e.,initiation and elongation) in rice remain largely unclear.Here,we report an AP2/ERF transcription factor,Hairy Leaf 6 (HL6),which controls trichome formation in rice.Functional analyses revealed that HL6 transcriptionally regulates trichome elongation in rice,which is dependent on functional OsWOX3B,a homeodomain-containing protein that acts as a key regulator in trichome initiation.Biochemical and molecular genetic analyses demonstrated that HL6 physically interacts with OsWOX3B,and both of them regulate the expression of some auxin-related genes during trichome formation,in which OsWOX3B likely enhances the binding ability of HL6 with one of its direct target gene,OsYUCCA5.Population genetic analysis indicated that HL6 was under negative selection during rice domestication.Taken together,our findings provide new insights into the molecular regulatory network of trichome formation in rice.

Seed development in angiosperms requires a 2∶1 maternal-to-paternal genome ratio (2m∶1p) in the endosperm.When the ratio is disrupted,the seed development is impaired.Rice interploidy crosses result in endosperm failures,but the underlying molecular mechanisms remain unclear.Here,we report that the defective endosperm in rice interploidy crosses was associated with nonadditive expression of small RNAs and protein-coding genes.Interestingly,24-nt small interfering RNAs were enriched in the 5'and 3'flanking sequences of nonadditively expressed genes in the interploidy crosses and were negatively associated with the expression of imprinted genes.Furthermore,some PRC2 family genes and DNA methylation-related genes including OsMET1b and OsCMT3a were upregulated in the 2x4 cross (pollinating a diploid "mother" with a tetraploid "father") but repressed in the reciprocal cross.These different epigenetic effects could lead to precocious or delayed cellularization during endosperm development.Notably,many endosperm-preferred genes,including starch metabolic and storage protein genes during grain filling,were found to be associated with DNA methylation or H3K27me3,which are repressed in both 2x4 and 4x2 crosses.WUSCHEL homeobox2 (WOX2)-like (WOX2L),an endosperm-preferred gene,was expressed specifically in the rice endosperm,in contrast to WOX2 expression in the Arabidopsis embryo.Disruption of WOX2L in transgenic rice by CRISPR/Cas9-mediated gene editing blocked starch and protein accumulation,resulting in seed abortion.In addition to gene repression,disrupting epigenetic process in the interploidy crosses also induced expression of stress-responsive genes.Thus,maintaining the 2m∶1p genome ratio in the endosperm is essential for normal grain development in rice and other cereal crops.

During embryogenesis, plants are thought to use a mechanism that allows the suspensor to maintain its identity.Here,we reported that RPL18aB is involved in this mechanism in Arabidopsis thaliana.The suspensor cells proliferated in rpl18aB and formed a multicellular structure rather than undergo pro-grammed cell death, as in wild type. Suspensors of rpl18aB expressed the embryo proper marker, DRN::GFP, but not the suspensor marker, WOX8::GFP. In addition,auxin accumulated throughout the suspensors of rpl18aB proembryos. Suspensor-specific expression of RPL18aB could rescue the cell proliferation defects in rpl18aB suspensors.These findings supported a role for RPL18aB in maintaining suspensor identity.

De nova root regeneration (DNRR) has wide applications in agriculture such as those related to cutting technology.Detached Arabidopsis thaliana leaf explants can regenerate adventitious roots without added hormones.The regenerative ability is highly dependent on the developmental status of the leaf.An immature leaf has a higher regenerative ability,while a mature leaf is difficult to regenerate.Using RNA-Seq analysis,we showed that the expression levels of many genes,including those in the auxin network,changed during leaf maturation.Particularly,the expression levels of many YUCCA (YUC) genes in the auxin biosynthesis pathway are responsive to leaf maturation.Overexpression of YUC1 in the yuc-1D dominant mutant rescued the rooting defects caused by leaf maturation,In addition,YUC4 expression levels were also affected by circadian rhythms.The regenerative ability was reduced in both immature and mature mutant leaf explants from the new wuschel-related homeobox 11-3 (wox11-3) and wox12-3 mutant alleles created by the CRISPR/Cas9 method.Overall,the transcriptome and genetic data,together with the auxin concentration analysis,indicate that the ability to upregulate auxin levels upon detachment may be reduced during leaf maturation.Thus,multiple developmental and environmental signals may converge to control auxin accumulation,which affects the efficiency of the WOX11/12-mediated DNRR from leaf explants.

WUSCHEL-related homeobox(WOX)家族是植物特有的转录因子家族,参与分生组织细胞分裂分化、初生和次生物质代谢及植物激素信号转导等多个发育过程,目前尚未有从全基因组分析该基因家族参与杨树茎部发育的相关研究.本项研究旨在对杨树WOX基因家族进行鉴定,在杨树基因中发现18个WOX候选基因,将这些候选基因分为三组,同一分组的大多数WOX家族成员具有相似的基因结构和保守的基序.根据不同发育阶段茎部转录组数据,系统分析了WOX家族成员在茎部不同发育阶段的特异表达情况,并采用qRT-PCR对上述结果进行了验证.结果 表明,杨树WOX基因家族在茎部不同发育阶段表现出不同的表达模式,为毛果杨WOX家族的功能研究与利用奠定基础.

植物种子是裸子植物和被子植物所特有的繁殖器官,也是人类赖以生存粮食的最主要来源.植物种子发育的过程包括形态发育和种子成熟,由一个复杂的转录因子网络管控,转录因子调控和监管整个发育过程.转录因子包含DNA结合区、寡聚化位点区、核定位信号区和转录调控区4个功能结构域,通过结构域与顺式元件相互作用调控基因的表达.研究表明,WOX家族调控胚芽发育,HAP3家族调控胚胎形态发生和细胞分化,MADS-box家族调控胚座和胚珠的发育,NAC家族调控胚珠珠被生长发育,bHLH家族调控种皮细胞的大小和形态,MYB家族是种皮发育的正调节因子.HAP家族成员LEC1和B3超家族的AFL亚家族成员LEC2、FUSCA3、ABI3一起互相作用形成一个调控网络,共同调控种子的成熟发育.Zinc finger超家族的Dof家族调控种子的胚乳发育、贮藏蛋白的合成及脂肪含量的变化,bZIP家族调控种子贮藏基因表达,AP2/EREBP家族调控种子体积与重量、蛋白与油类积累,WRKY家族、IKU、MINI3、SHB1基因和KLU基因调控种子体积大小.综述了植物种子发育过程中转录因子的结构和种类,分析了其作用顺序和功能,解析了种子发育的分子调控机制,展望了其研究方向和前景,以期为种子品质改良奠定理论基础和提供新的思路.