No abstract

SummaryAlthough hundreds of genetic male sterility (GMS) mutants have been identified in maize, few are commercially used due to a lack of effective methods to produce large quantities of pure male‐sterile seeds. Here, we develop a multicontrol sterility (MCS) system based on the maize male sterility 7 (ms7) mutant and its wild‐type Zea mays Male sterility 7 (ZmMs7) gene via a transgenic strategy, leading to the utilization of GMS in hybrid seed production. ZmMs7 is isolated by a map‐based cloning approach and encodes a PHD‐finger transcription factor orthologous to rice PTC1 and Arabidopsis MS1. The MCS transgenic maintainer lines are developed based on the ms7‐6007 mutant transformed with MCS constructs containing the (i) ZmMs7 gene to restore fertility, (ii) α‐amylase gene ZmAA and/or (iii) DNA adenine methylase gene Dam to devitalize transgenic pollen, (iv) red fluorescence protein gene DsRed2 or mCherry to mark transgenic seeds and (v) herbicide‐resistant gene Bar for transgenic seed selection. Self‐pollination of the MCS transgenic maintainer line produces transgenic red fluorescent seeds and nontransgenic normal colour seeds at a 1:1 ratio. Among them, all the fluorescent seeds are male fertile, but the seeds with a normal colour are male sterile. Cross‐pollination of the transgenic plants to male‐sterile plants propagates male‐sterile seeds with high purity. Moreover, the transgene transmission rate through pollen of transgenic plants harbouring two pollen‐disrupted genes is lower than that containing one pollen‐disrupted gene. The MCS system has great potential to enhance the efficiency of maize male‐sterile line propagation and commercial hybrid seed production.

Previous studies have shown that haploinsufficiency of the splanchnic and septum transversum mesoderm Forkhead Box (Fox) f1 transcriptional factor caused defects in lung and gallbladder development and that Foxf1 heterozygous (؉/؊) mice exhibited defective lung repair in response to injury. In this study, we show that Foxf1 is expressed in hepatic stellate cells in developing and adult liver, suggesting that a subset of stellate cells originates from septum transversum mesenchyme during mouse embryonic development. Because liver regeneration requires a transient differentiation of stellate cells into myofibroblasts, which secrete type I collagen into the extracellular matrix, we examined Foxf1 ؉/؊ liver repair following carbon tetrachloride injury, a known model for stellate cell activation. We found that regenerating Foxf1 ؉/؊ liver exhibited defective stellate cell activation following CCl 4 liver injury, which was associated with diminished induction of type I collagen, ␣-smooth muscle actin, and Notch-2 protein and resulted in severe hepatic apoptosis despite normal cellular proliferation rates. Furthermore, regenerating Foxf1 ؉/؊ livers exhibited decreased levels of interferon-inducible protein 10 (IP-10), delayed induction of monocyte chemoattractant protein 1 (MCP-1) levels, and aberrantly elevated expression of transforming growth factor ␤1. T he Forkhead Box (Fox) family of transcription factors shares homology in the winged helix DNA binding domain, 1 and its members play important roles in cellular proliferation, differentiation, and metabolic homeostasis. [2][3][4][5][6] Haploinsufficiency of the Foxf1 gene (previously known as HFH-8 or Freac-1) in heterozygous (ϩ/Ϫ) mice causes perinatal lethality from pulmonary hemorrhage and severe defects in alveolarization, vascularization, and fusion of lung lobes. 7-9 Lung hemorrhage was observed in one half of newborn Foxf1 ϩ/Ϫ mice that had an 80% reduction in pulmonary Foxf1 levels (low Foxf1 ϩ/Ϫ) and reduced expression of genes involved in lung morphogenesis. 7 Interestingly, expression of these lung developmental genes was unchanged in 40% of the newborn Foxf1 ϩ/Ϫ mice that had near wildtype (WT) pulmonary levels of Foxf1 messenger RNA (mRNA) (high Foxf1 ϩ/Ϫ mice) without pulmonary hemorrhage, but they exhibited diminished alveolar septation. 7 Moreover, the high Foxf1 ϩ/Ϫ mice had normal life spans and adult lung morphology, suggesting that these mice compensated for the alveolar septation defect but exhibited defective lung repair in response to injury. 10 Liver development initiates at 9 days postcoitum (dpc) of mouse embryogenesis, when the cardiac mesenchyme induces the hepatic primordium to emerge from the foregut endoderm that invades the septum transversum mesenchyme. 6 Previous expression studies have shown

Genic male sterility (GMS) is very useful for hybrid vigor utilization and hybrid seed production. Although a large number of GMS genes have been identified in plants, little is known about the roles of GDSL lipase members in anther and pollen development. Here, we report a maize GMS gene, ZmMs30, which encodes a novel type of GDSL lipase with diverged catalytic residues. Enzyme kinetics and activity assays show that ZmMs30 has lipase activity and prefers to substrates with a short carbon chain. ZmMs30 is specifically expressed in maize anthers during stages 7-9. Loss of ZmMs30 function resulted in defective anther cuticle, irregular foot layer of pollen exine, and complete male sterility. Cytological and lipidomics analyses demonstrate that ZmMs30 is crucial for the aliphatic metabolic pathway required for pollen exine formation and anther cuticle development. Furthermore, we found that male sterility caused by loss of ZmMs30 function was stable in various inbred lines with different genetic background, and that it didn't show any negative effect on maize heterosis and production, suggesting that ZmMs30 is valuable for crossbreeding and hybrid seed production. We then developed a new multi-control sterility system using ZmMs30 and its mutant line, and demonstrated it is feasible for generating desirable GMS lines and valuable for hybrid maize seed production. Taken together, our study sheds new light on the mechanisms of anther and pollen development, and provides a valuable male-sterility system for hybrid breeding maize.

Amelogenin expression is ameloblast-specific and developmentally regulated at the temporal and spatial levels. In a previous transgenic mouse analysis, the expression pattern of the endogenous amelogenin gene was recapitulated by a reporter gene driven by a 2.2-kilobase mouse amelogenin proximal promoter. To understand the molecular mechanisms underlying the spatiotemporal expression of the amelogenin gene during odontogenesis, the mouse amelogenin promoter was systematically analyzed in mouse ameloblast-like LS8 cells. Deletion analysis identified a minimal promoter (؊70/؉52