To protect above‐ground plant organs from excessive water loss, their surfaces are coated by waxes. The genes involved in wax formation have been investigated in detail in Arabidopsis but scarcely in crop species. Here, we aimed to isolate and characterize a CER1 enzyme responsible for formation of the very long‐chain alkanes present in high concentrations especially during late stages of wheat development. On the basis of comparative wax and transcriptome analyses of various wheat organs, we selected TaCER1‐1A as a primary candidate and demonstrated that it was located to the endoplasmic reticulum, the subcellular compartment for wax biosynthesis. A wheat nullisomic‐tetrasomic substitution line lacking TaCER1‐1A had significantly reduced amounts of C33 alkane, whereas rice plants overexpressing TaCER1‐1A showed substantial increases of C25–C33 alkanes relative to wild type control. Similarly, heterologous expression of TaCER1‐1A in Arabidopsis wild type and the cer1 mutant resulted in increased levels of unbranched alkanes, iso‐branched alkanes and alkenes. Finally, the expression of TaCER1‐1A was found activated by abiotic stresses and abscisic acid treatment, resulting in increased production of alkanes in wheat. Taken together, our results demonstrate that TaCER1‐1A plays an important role in wheat wax alkane biosynthesis and involved in responding to drought and other environmental stresses.

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Background. Xenogeneic organ transplantation has been proposed as a potential approach to fundamentally solve organ shortage problem. Xenogeneic immune responses across species is one of the major obstacles for clinic application of xeno-organ transplantation. The generation of glycoprotein galactosyltransferase α 1, 3 (GGTA1) knockout pigs has greatly contributed to the reduction of hyperacute xenograft rejection. However, severe xenograft rejection can still be induced by xenoimmune responses to the porcine major histocompatibility complex antigens swine leukocyte antigen class I and class II. Methods. We simultaneously depleted GGTA1, β2-microglobulin (β2M), and major histocompatibility complex class II transactivator (CIITA) genes using clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins technology in Bamma pig fibroblast cells, which were further used to generate GGTA1 −/− β2M −/− CIITA −/− triple knockout (GBC-3KO) pigs by nuclear transfer. Results. The genotype of GBC-3KO pigs was confirmed by polymerase chain reaction and Sanger sequencing, and the loss of expression of α-1,3-galactose, SLA-I, and SLA-II was demonstrated by flow cytometric analysis using fluorescent-conjugated lectin from bandeiraea simplicifolia, anti-β2-microglobulin, and swine leukocyte antigen class II DR antibodies. Furthermore, mixed lymphocyte reaction assay revealed that peripheral blood mononuclear cells from GBC-3KO pigs were significantly less effective than (WT) pig peripheral blood mononuclear cells in inducing human CD3+CD4+ and CD3+CD8+ T-cell activation and proliferation. In addition, GBC-3KO pig skin grafts showed a significantly prolonged survival in immunocompetent C57BL/6 mice, when compared with wild-type pig skin grafts. Conclusions. Taken together, these results demonstrate that elimination of GGTA1, β2M, and CIITA genes in pigs can effectively alleviate xenogeneic immune responses and prolong pig organ survival in xenogenesis. We believe that this work will facilitate future research in xenotransplantation.

Aims: As a natural antimicrobial agent, Melaleuca alternifolia oil (MAO) is generally recognized to be safe and effective in the inhibition of phytopathogenic fungi. Due to lack of comprehensive studies on MAO for controlling postharvest Aspergillus, we investigated the preservative mechanism of MAO and its components against Aspergillus ochraceus in postharvest grapes to evaluate their potential effectiveness as fruit preservatives. Methods and Results: In our study, the compositions in MAO were analysed by gas chromatography-mass spectrometry. The inhibitory effects of MAO and its main constituents against A. ochraceus were compared by scanning electron microscopy and transmission electron microscopy observation, and metabolic analysis. Two components of MAO, a-terpineol and terpene-4-alcohol, showed higher antifungal effects than MAO, of which a-terpineol caused the worst leakage of cytoplasm and most serious hyphae distortions and spore disruptions. The downregulation of metabolic pathways of A. ochraceus was strongest with a-terpineol. The best inhibitory efficacy against A. ochraceus in grapes also occurred with a-terpineol. 3-Carene showed little inhibitory effect. Conclusions: These results demonstrate that not all components in MAO possess antimicrobial effects, and a-terpineol is the main contributor of MAO's A. ochraceus inhibition effect. Significance and Impact of the Study: a-Terpineol may be used as an alternative natural preservative for the postharvest storage of grapes and other fruits.

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