Proteomic identification of potential target proteins regulated by an ASK1-mediated proteolysis pathway

ASK1 (ARABIDOPSIS 象 SKP1 一样) 蛋白质是招募的 ubiquitin ligase 建筑群指向的 SCF (Skp1-Cullin-F 盒子蛋白质) 的一个批评部件为由 26S proteosome 的降级的蛋白质。为了调查蛋白质，那被调停 ASK1 的解朊作用小径在 Arabidopsis 花影响，我们用二维的电气泳动(2-DE ) 比较了 Arabidopsis 野类型和 ask1 异种花芽的 proteomes。有在与野类型花相比的 ask1 异种花的更高或更低的丰富的十个蛋白质点被切除并且使分析遭到了到进一步集体的 spectrometry (MS ) 。结果证明他们是涉及相片形态发生，生理节奏的摆动，翻译以后的过程，压力反应和房间扩大或延伸的蛋白质，建议那些过程在 ask1 异种被影响。基因也是的这些的抄本层次基于 Affymetrix 基因芯片比较了微数组数据。没有重要差别为大多数基因被观察，建议有在 ask1 异种的累积的提高的层次的蛋白质能是一条调停 ASK1 的解朊作用小径调整的候选人目标。阐明的这些结果帮助在 Arabidopsis 发展过程并且也的 ASK1 的多种的功能表明关于基因功能学习蛋白质层次的重要性和必要性。

Orientation and ellipticity dependence of high-order harmonic generation in nanowires

It has been predicted that high-order harmonic generation(HHG) in nanowires has the potential to scale up photon energy and harmonic yield.However,studies on HHG in nanowires are still theoretical and no relevant experimental results have been reported as yet.Our experimental observation of the high-order harmonic in cadmium sulfide nanowires(CdS NWs) excited by a mid-infrared laser is,to our knowledge,the first of such study,and it verifies some of the theoretical results.Our experimental results show that the observed harmonics are strongest when a pump laser is parallel to the nanowires.Therefore,the theoretical prediction that harmonics are strongest under the nanowires parallel to the laser field is confirmed experimentally,and this can be used to determine the orientation of the nanowire.In addition,harmonics are sensitive to the variation of pump light ellipticities.This orientation dependence opens new opportunities to access the ultrafast and strong-field physics of nanowires.

Rice Male Development under Drought Stress： Phenotypic Changes and Stage-Dependent Transcriptomic Reprogramming

Drought affects rice reproduction and results in severe yield loss. The developmental defects and changes of gene regulation network in reproductive tissues under drought stress are largely unknown. In this study, rice plants subjected to reproductive stage drought stress were examined for floral development and transcriptomic changes. The results showed that male fertility was dramatically affected, with differing pollen viability in flowers of the same panicle due to aberrant anther development under water stress. Examination of local starch distribution revealed that starch accumulated abnormally in terms of position and abundance in anthers of water-stressed plants. Microarray analysis using florets of different sizes identified 〉1000 drought-responsive genes, most of which were specifically regulated in only one or two particular sizes of florets, suggesting developmental stage-dependent responses to drought. Genes known to be involved in tapetum and/or microspore development, cell wall formation or expansion, and starch synthesis were found more frequently among the genes affected by drought than genome average, while meiosis and MADS-box genes were less frequently affected. In addition, pathways related to gibberellin acid signal- ing and abscisic acid catabolism were reprogrammed by drought. Our results strongly suggest interactions between reproductive development, phytohormone signaling, and carbohydrate metabolism in water-stressed plants.

Changing Gly311 to an acidic amino acid in the MATE family protein DTX6 enhances Arabidopsis resistance to the dihydropyridine herbicides

In modern agriculture,frequent application of herbicides may induce the evolution of resistance in plants,but the mechanisms underlying herbicide resistance remain largely unexplored.Here,we report the char-acterization of rtp 1(resistant to paraquat 1),an Arabidopsis mutant showing strong resistance to the widely used herbicides paraquat and diquat.The rtp1 mutant is semi-dominant and carries a point mutation in the gene encoding the multidrug and toxic compound extrusion family protein DTX6,leading to the change of glycine to glutamic acid at residue 311(G311E).The wild-type DTX6 with glycine 311 conferred weak para-quat and diquat resistance when overexpressed,while mutation of glycine 311 to a negatively charged amino acid(G311E or G311D)markedly increased the paraquat and diquat resistance of plants,whereas mutation to a positively charged amino acid(G311R or G311K)compromised the resistance,suggesting that the charge property of residue 311 of DTX6 is critical for the paraquat and diquat resistance of Arabi-dopsis plants.DTX6 is localized in the endomembrane trafficking system and may undergo the endosomal sorting to localize to the vacuole and plasma membrane.Treatment with the V-ATPase inhibitor ConA reduced the paraquat resistance of the rtp1 mutant.Paraquat release and uptake assays demonstrated that DTX6 is involved in both exocytosis and vacuolar sequestration of paraquat.DTX6 and DTX5 show functional redundancy as the dtx5 dtx6 double mutant but not the dtx6 single mutant plants were more sen-sitive to paraquat and diquat than the wild-type plants.Collectively,our work reveals a potential mecha-nism for the evolution of herbicide resistance in weeds and provides a promising gene for the manipulation of plant herbicide resistance.

Poly(ADP-ribose) polymerases regulate cell division and development in Arabidopsis roots

Root organogenesis involves cell division, differentiation and expansion. The molecular mechanisms regulating root development are not fully understood. In this study, we identified poly（adenosine diphosphate （ADP）-ribose） polymerases （PARPs） as new players in root development. PARP catalyzes poly（ADP-ribosyl）ation of proteins by repeatedly adding ADP-ribose units onto proteins using nicotinamide adenine dinucleotide （NAD ） as the donor. We found that inhibition of PARP activities by 3-aminobenzomide （3-AB） increased the growth rates of both primary and lateral roots, leading to a more developed root system. The double mutant of Arabidopsis PARPs, parplparp2, showed more rapid primary and lateral root growth. Cyclin genes regulating G1-to-S and G2-to-M transition were up-regulated upon treatment by 3-AB. The proportion of 2C ceils increased while cells with higher DNA ploidy declined in the roots of treated plants, resulting in an enlarged root meristematic zone. The expression level of PARP2 was very low in the meristematic zone but high in the maturation zone, consistent with a role of PARP in inhibiting mitosis and promoting cell differentiation. Our results suggest that PARPs play an important role in root development by negatively regulating root cell division.