Gene expression and metabolite profiles of cotton fiber during cell elongation and secondary cell wall synthesis

棉花纤维在延伸的开始以后很快伸长，最后导致大量纤维素的存款。为了在快延伸和第二等的细胞壁合成揭示棉花纤维房间的特征，上演，我们比较了 respectivetranscriptomes 和代谢物侧面。由 cDNA 数组的 transcriptomes 的比较分析识别了是在纤维开发期间调整的差别的 633 基因。用变量把纤维样品划分了成四的表示基因的 Principalcomponent 分析(PCA ) 组织，它发育阶段是诊断的。如果，类似的组织结果也被发现我们是的 usenon 极或极的代谢物为开发纤维的 PCA 的变量。植物生长素发信号，松开墙并且脂类代谢在纤维延伸期间是高度活跃的，而纤维素生合成是占优势的，许多另外的新陈代谢的小径是在第二等的细胞壁合成调整的 down，上演。抄本和代谢物侧面和酶活动在向纤维素合成表明棉花纤维开发的一个专门化过程是一致的。这些数据证明在某个阶段的那个棉花纤维房间有它棉花纤维房间的自己的唯一的特征，和发育阶段能被他们的抄本和代谢物侧面区分。在第二等的细胞壁合成阶段期间，新陈代谢的小径被流进纤维素合成。

Suppression of ZEAXANTHIN EPOXIDASE 1 restricts stripe rust growth in wheat

Reducing losses caused by pathogens is an effective strategy for stabilizing crop yields.Daunting challenges remain in cloning and characterizing genes that inhibit stripe rust,a devastating disease of wheat(Triticum aestivum)caused by Puccinia striiformis f.sp.tritici(Pst).We found that suppression of wheat zeaxanthin epoxidase 1(ZEP1)increased wheat defense against Pst.We isolated the yellow rust slower 1(yrs1)mutant of tetraploid wheat in which a premature stop mutation in ZEP1-B underpins the phenotype.Genetic analyses revealed increased H_(2)O_(2) accumulation in zep1 mutants and demonstrated a correlation between ZEP1 dysfunction and slower Pst growth in wheat.Moreover,wheat kinase START 1.1(WKS1.1,Yr36)bound,phosphorylated,and suppressed the biochemical activity of ZEP1.A rare natural allele in the hexaploid wheat ZEP1-B promoter reduced its transcription and Pst growth.Our study thus identified a novel suppressor of Pst,characterized its mechanism of action,and revealed beneficial variants for wheat disease control.This work opens the door to stacking wheat ZEP1 variants with other known Pst resistance genes in future breeding programs to enhance wheat tolerance to pathogens.

A Cotton BURP Domain Protein Interacts With α-Expansin and Their Co-Expression Promotes Plant Growth and Fruit Production

Plant growth requires cell wall extension. The cotton AtRD22-Like I gene GhRDL1, predominately expressed in elongating fiber cells, encodes a BURP domain-containing protein. Here, we show that GhRDL1 is localized in cell wall and interacts with GhEXPA1, an α-expansin functioning in wall loosening. Transgenic cotton overexpressing GhRDL1 showed an increase in fiber length and seed mass, and an enlargement of endopleura cells of ovules. Expression of either GhRDL1 or GhEXPA1 alone in Arabidopsis led to a substantial increase in seed size; interestingly, their co-expression resulted in the increased number of siliques, the nearly doubled seed mass, and the enhanced biomass production. Cotton plants overexpressing GhRDL1 and GhEXPA1 proteins produced strikingly more fruits （bolls）, leading to up to 40% higher fiber yield per plant without adverse effects on fiber quality and vegetative growth. We demonstrate that engineering cell wall protein partners has a great potential in promoting plant growth and crop yield.

YR36/WKS1-Mediated Phosphorylation of PsbO,an Extrinsic Member of Photosystem Ⅱ,Inhibits Photosynthesis and Confers Stripe Rust Resistance in Wheat

Wheat stripe rust,due to infection by Puccinia striiformis f.sp.tritici(Pst),is a devastating disease that causes significant global grain yield losses.Yr36,which encodes Wheat Kinase START1(WKS1),is an effec-tive high-temperature adult-plant resistance gene and confers resistance to a broad spectrum of Pst races.We previously showed that WKS1 phosphorylates the thylakoid ascorbate peroxidase protein and reduces its ability to detoxify peroxides,which may contribute to the accumulation of reactive oxygen species(ROS).WKS1-mediated Pst resistance is accompanied by leaf chlorosis in Pst-infected regions,but the un-derlying mechanisms remain elusive.Here,we show that WKS1 interacts with and phosphorylates PsbO,an extrinsic member of photosystem Ⅱ(PS Ⅱ),to reduce photosynthesis,regulate leaf chlorosis,and confer Pst resistance.A point mutation in PsbO-A1 or reduction in its transcript levels by RNA interference resulted in chlorosis and reduced Pst sporulation.Biochemical analyses revealed that WKS1 phosphorylates PsbO at two conserved amino acids involved in physical interactions with PS Ⅱ and reduces the binding affinity of PsbO with PS Ⅱ.Presumably,phosphorylated PsbO proteins dissociate from the PS Ⅱ complex and then un-dergo rapid degradation by cysteine and aspartic proteases.Taken together,these results demonstrate that perturbations of wheat PsbO by point mutation or phosphorylation by WKS1 reduce the rate of photo-synthesis and delay the growth of Pst pathogen before the induction of ROS.

Characterization and Ectopic Expression of a Populus Hydroxyacid Hyd roxyci n nam oylt ra nsferase

Cutinized and suberized cell walls in plants constitute physiologically important environment interfaces. They act as barriers limiting the loss of water and nutrients and protecting against radiation and invasion of pathogens. The roles of cutin- and suberin polyesters are often attributed to their dominant aliphatic components, but the contri- bution of aromatic composition to their physiological function remains unclear. By functionally screening a subset of Populus trichocarpa BAHD/HXXXD acyltransferases, we identified a hydroxycinnamoyltransferase that shows specific transacylation activity on ~0-hydroxyacids using both feruloyl- and p-coumaroyl- CoA as the acyl donors. We named this enzyme P. trichocarpa hydroxyacid/fatty alcohol hydroxycinnamoyltransferase 1 （PtFHT1）. The ectopic expression of the PtFHT1 gene in Arabidopsis increased the incorporation of ferulate in root and seed suberins and in leaf cutin, but not that of p-coumarate, while the aliphatic load in both suberin and cutin polyesters essentially remained unaffected. The overaccumulation of ferulate in lipophilic polyester significantly increased the tolerance of transgenic plants to salt stress treatment; under sub-lethal conditions of salt stress, the ratios of their seed germination and seedling establishment were 50% higher than those of wild-type plants. Our study suggests that, although aromatics are the minor component of polyesters, they play important role in the sealing function of lipidic polymers in planta.