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981.
Plants depend on gravity to provide the constant landmark for downward root growth and upward shoot growth. The phytohormone auxin and its cell‐to‐cell transport machinery are central determinants ensuring gravitropic growth. Statolith sedimentation toward gravity is sensed in specialized cells. This positional cue is translated into the polar distribution of PIN auxin efflux carriers at the plasma membrane, leading to asymmetric auxin distribution and consequently, differential growth and organ bending. While we have started to understand the general principles of how primary organs execute gravitropism, we currently lack basic understanding of how lateral plant organs can defy gravitropic responses. Here we briefly review the establishment of the oblique gravitropic set point angle in lateral roots and particularly discuss the emerging role of asymmetric cytokinin signaling as a central anti‐gravitropic signal. Differential cytokinin signaling is co‐opted in gravitropic lateral and hydrotropic primary roots to counterbalance gravitropic root growth. 相似文献
982.
983.
Bo‐Wen Gu Lian‐Mei Tan Cui‐Jun Zhang Xiao‐Mei Hou Xue‐Wei Cai She Chen Xin‐Jian He 《植物学报(英文版)》2020,62(11):1703-1716
Imitation Switch (ISWI) chromatin remodelers are known to function in diverse multi‐subunit complexes in yeast and animals. However, the constitution and function of ISWI complexes in Arabidopsis thaliana remain unclear. In this study, we identified forkhead‐associated domain 2 (FHA2) as a plant‐specific subunit of an ISWI chromatin‐remodeling complex in Arabidopsis. By in vivo and in vitro analyses, we demonstrated that FHA2 directly binds to RLT1 and RLT2, two redundant subunits of the ISWI complex in Arabidopsis. The stamen filament is shorter in the fha2 and rlt1/2 mutants than in the wild type, whereas their pistil lengths are comparable. The shorter filament, which is due to reduced cell size, results in insufficient pollination and reduced fertility. The rlt1/2 mutant shows an early‐flowering phenotype, whereas the phenotype is not shared by the fha2 mutant. Consistent with the functional specificity of FHA2, our RNA‐seq analysis indicated that the fha2 mutant affects a subset of RLT1/2‐regulated genes that does not include genes involved in the regulation of flowering time. This study demonstrates that FHA2 functions as a previously uncharacterized subunit of the Arabidopsis ISWI complex and is exclusively involved in regulating stamen development and plant fertility. 相似文献
984.
Yann‐Ru Lou Sheaza Ahmed Jian Yan Adewale M. Adio Hannah M. Powell Paul F. Morris Georg Jander 《植物学报(英文版)》2020,62(5):601-613
Polyamines are small aliphatic amines found in almost all organisms, ranging from bacteria to plants and animals. In most plants, putrescine, the metabolic precursor for longer polyamines, such as spermidine and spermine, is produced from arginine, with either agmatine or ornithine as intermediates. Here we show that Arabidopsis thaliana(Arabidopsis) arginine decarboxylase 1(ADC1), one of the two known arginine decarboxylases in Arabidopsis, not only synthesizes agmatine from arginine, but also converts N~δ-acetylornithine to N-acetylputrescine. Phylogenetic analyses indicate that duplication and neofunctionalization of ADC1 and NATA1, the enzymes that synthesize N~δ-acetylornithine in Arabidopsis, co-occur in a small number of related species in the Brassicaceae. Unlike ADC2, which is localized in the chloroplasts, ADC1 is in the endoplasmic reticulum together with NATA1, an indication that these two enzymes have access to the same substrate pool. Together, these results are consistent with a model whereby NATA1 and ADC1 together provide a pathway for the synthesis of N-acetylputrescine in Arabidopsis. 相似文献
985.
Tao Guo Ke Chen Nai‐Qian Dong Wang‐Wei Ye Jun‐Xiang Shan Hong‐Xuan Lin 《植物学报(英文版)》2020,62(5):581-600
Auxin is a crucial phytohormone, controlling multiple aspects of plant growth and responses to the changing environment. However, the role of local auxin biosynthesis in specific developmental programs remains unknown in crops. This study characterized the rice tillering and small grain 1 (tsg1) mutant, which has more tillers but a smaller panicle and grain size resulting from a reduction in endogenous auxin. TSG1 encodes a tryptophan aminotransferase that is allelic to the FISH BONE (FIB) gene. The tsg1 mutant showed hypersensitivity to indole‐3‐acetic acid and the competitive inhibitor of aminotransferase, L‐kynurenine. TSG1 knockout resulted in an increased tiller number but reduction in grain number and size, and decrease in height. Meanwhile, deletion of the TSG1 homologs OsTAR1, OsTARL1, and OsTARL2 caused no obvious changes, although the phenotype of the TSG1/OsTAR1 double mutant was intensified and infertile, suggesting gene redundancy in the rice tryptophan aminotransferase family. Interestingly, TSG1 and OsTAR1, but not OsTARL1 and OsTARL2, displayed marked aminotransferase activity. Meanwhile, subcellular localization was identified as the endoplasmic reticulum, while phylogenetic analysis revealed functional divergence of TSG1 and OsTAR1 from OsTARL1 and OsTARL2. These findings suggest that TSG1 dominates the tryptophan aminotransferase family, playing a prominent role in local auxin biosynthesis in rice. 相似文献
986.
Zipeng Yu Yang Xu Lifei Zhu Lei Zhang Lin Liu Di Zhang Dandan Li Changai Wu Jinguang Huang Guodong Yang Kang Yan Shizhong Zhang Chengchao Zheng 《植物学报(英文版)》2020,62(4):403-420
Low molecular weight secreted peptides have recently been shown to affect multiple aspects of plant growth, development, and defense responses.Here, we performed stepwise BLAST filtering to identify unannotated peptides from the Arabidopsis thaliana protein database and uncovered a novel secreted peptide family, secreted transmembrane peptides(STMPs). These low molecular weight peptides, which consist of an N-terminal signal peptide and a transmembrane domain, were primarily localized to extracellular compartments but were also detected in the endomembrane system of the secretory pathway, including the endoplasmic reticulum and Golgi. Comprehensive bioinformatics analysis identified 10 STMP family members that are specific to the Brassicaceae family. Brassicaceae plants showed dramatically inhibited root growth uponexposure to chemically synthesized STMP1 and STMP2.Arabidopsis overexpressing STMP1, 2, 4, 6, or 10 exhibited severely arrested growth, suggesting that STMPs are involved in regulating plant growth and development. In addition, in vitro bioassays demonstrated that STMP1,STMP2, and STMP10 have antibacterial effects against Pseudomonas syringae pv. tomato DC3000, Ralstonia solanacearum, Bacillus subtilis, and Agrobacterium tumefaciens, demonstrating that STMPs are antimicrobial peptides. These findings suggest that STMP family members play important roles in various developmental events and pathogen defense responses in Brassicaceae plants. 相似文献
987.
Qing‐Ping Zhao Jin‐Dong Zhu Nan‐Nan Li Xiao‐Nan Wang Xiang Zhao Xiao Zhang 《植物学报(英文版)》2020,62(5):614-630
Both phototropins(phot1 and phot2) and cryptochromes(cry1 and cry2) were proven as the Arabidopsis thaliana blue light receptors. Phototropins predominately function in photomovement, and cryptochromes play a role in photomorphogenesis. Although cryptochromes have been proposed to serve as positive modulators of phototropic responses, the underlying mechanism remains unknown. Here, we report that depleting sucrose from the medium or adding gibberellic acids(GAs) can partially restore the defects in phototropic curvature of the phot1 phot2 double mutants under high-intensity blue light; this restoration does not occur in phot1 phot2 cry1 cry2 quadruple mutants and nph3(nonphototropic hypocotyl 3) mutants which were impaired phototropic response in sucrose-containing medium. These results indicate that GAs and sucrose antagonistically regulate hypocotyl phototropism in a cryptochromes dependent manner, but it showed a crosstalk with phototropin signaling on NPH3.Furthermore, cryptochromes activation by blue light inhibit GAs synthesis, thus stabilizing DELLAs to block hypocotyl growth, which result in the higher GAs content in the shade side than the lit side of hypocotyl to support the asymmetric growth of hypocotyl. Through modulation of the abundance of DELLAs by sucrose depletion or added GAs, it revealed that cryptochromes have a function in mediating phototropic curvature. 相似文献
988.
Natural variation in the promoter of OsHMA3 contributes to differential grain cadmium accumulation between Indica and Japonica rice 总被引:1,自引:0,他引:1
Chao‐Lei Liu Zhen‐Yu Gao Lian‐Guang Shang Chang‐Hong Yang Ban‐Pu Ruan Da‐Li Zeng Long‐Biao Guo Fang‐Jie Zhao Chao‐Feng Huang Qian Qian 《植物学报(英文版)》2020,62(3):314-329
Rice is a major source of cadmium(Cd) intake for Asian people. Indica rice usually accumulates more Cd in shoots and grains than Japonica rice. However, underlying genetic bases for differential Cd accumulation between Indica and Japonica rice are still unknown. In this study, we cloned a quantitative trait locus(QTL) grain Cd concentration on chromosome 7(GCC7) responsible for differential grain Cd accumulation between two rice varieties by performing QTL analysis and map-based cloning. We found that the two GCC7 alleles, GCC7~(PA64s) and GCC7~(93-11), had different promoter activity of OsHMA3,leading to different OsHMA3 expression and different shoot and grain Cd concentrations. By analyzing the distribution of different haplotypes of GCC7 among diverse rice accessions, we discovered that the high and low Cd accumulation alleles, namely GCC7~(93-11) and GCC7~(PA64s), were preferentially distributed in Indica and Japonica rice,respectively. We further showed that the GCC7~(PA64s)allele can be used to replace the GCC7~(93-11) allele in the super cultivar 93-11 to reduce grain Cd concentration without adverse effect on agronomic traits. Our results thus reveal that the QTL GCC7 with sequence variation in the OsHMA3 promoter is an important determinant controlling differential grain Cd accumulation between Indica and Japonica rice. 相似文献
989.
990.
近年来,中国诸多大中城市内涝灾害频发。武汉市作为城市内涝频发的典型城市,其建成区地表高度(20.0~24.0 m)大多低于外江常年所处的洪水位高度(23.9 m),在区域性暴雨条件下,极易引发内涝灾害。武汉由于其内涝典型性,2013年被列为全国31个重点防洪城市之一,2015年被列入首批海绵城市试点城市之一。从城市内涝发生机理出发,以水文角度的小流域单元作为内涝风险区划的基本单元,利用小流域单元分析武汉市景观地形要素(地表高程、地表起伏度、地表粗糙度)与城市内涝积水密度的相关性及其影响程度,量算统计出小流域单元的内涝风险等级。基于此,提出武汉市小流域单元减灾地形调控评价。以武汉市作为城市内涝问题的研究案例,以期为武汉市内涝缓解提供新的思考路径,具有典型性和必要性。 相似文献