Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observa-tion showed that it is a begomovirus. In reactions with 14 ...Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observa-tion showed that it is a begomovirus. In reactions with 14 monoclonal antibodies raised against begomoviruses, Y1 was readily differentiated from begomoviruses reported in China, Pakistan and India. The complete nucleotide sequence of DNA-A was determined, it contains 2746 nucleotides, with two ORFs in virion-sense DNA and four ORFs in comple-mentary-sense DNA. Comparisons with total DNA-A, inter-genie region and deduced amino acid sequences of individual ORFs showed that Y1 is a distinct Begomovirus species, for which the name Tobacco curly shoot virus (TCSV) is pro-posed. The total DNA-A of TCSV is most closely related to that of Tomato leaf curl virus from India (85% sequence identity). In contrast, the deduced coat protein of TCSV is most like that of Cotton leaf curl virus 72b isolate from Paki-stan (98% amino acid sequence identity).展开更多
Plant hormones regulate many aspects of plant growth and development. Both auxin and cytokinin have been known for a long time to act either synergistically or antagonistically to control several significant developme...Plant hormones regulate many aspects of plant growth and development. Both auxin and cytokinin have been known for a long time to act either synergistically or antagonistically to control several significant developmental processes, such as the formation and maintenance of meristem. Over the past few years, exciting progress has been made to reveal the molecular mechanisms underlying the auxin-cytokinin action and interaction. In this review, we shall briefly discuss the major progress made in auxin and cytokinin biosynthesis, auxin transport, and auxin and cytokinin signaling. The frameworks for the complicated interaction of these two hormones in the control of shoot apical meristem and root apical meristem formation as well as their roles in in vitro organ regeneration are the major focus of this review.展开更多
MicroRNAs （miRNAs） are -21-nucleotide noncoding RNAs that play critical roles in regulating plant growth and development through directing the degradation of target mRNAs. Axillary meristem activity, and hence shoot...MicroRNAs （miRNAs） are -21-nucleotide noncoding RNAs that play critical roles in regulating plant growth and development through directing the degradation of target mRNAs. Axillary meristem activity, and hence shoot branching, is influenced by a complicated network that involves phytohormones such as auxin, cytokinin, and strigolactone. GAI, RGA, and SCR （GRAS） family members take part in a variety of developmental processes, including axillary bud growth. Here, we show that the Arabidopsis thaliana microRNA171c （miR171c） acts to negatively regulate shoot branching through targeting GRAS gene family members SCARECROW-LIKE6-Ⅱ （SCL6-Ⅱ）, SCL6-Ⅲ, and SCL6-Ⅳ for cleavage. Transgenic plants overexpressing MIR171c （35Spro-MIR171c） and sd6-Ⅱ scl6-Ⅲ scl6-Ⅳ triple mutant plants exhibit a similar reduced shoot branching phenotype. Expression of any one of the miR171c-resistant versions of SCL6-Ⅱ, SCL6-Ⅲ, and SCL6-Ⅳ in 35Spro- MIR171c plants rescues the reduced shoot branching phenotype. Scl6-Ⅱ scl6-Ⅲ scl6-Ⅳ mutant plants exhibit pleiotropic phenotypes such as increased chlorophyll accumulation, decreased primary root elongation, and abnormal leaf and flower patterning. SCL6-Ⅱ, SCL6-Ⅲ, and SCL6-Ⅳ are located to the nucleus, and show transcriptional activation activity. Our results suggest that miR171c-targeted SCL6-Ⅱ, SCL6-Ⅲ, and SCL6-Ⅳ play an important role in the regulation of shoot branch production.展开更多
The tea green leafhopper, Empoasca vitis Gothe, is one of the most serious insect pests of tea plantations in China's Mainland. Over the past decades, this pest has been controlled mainly by spraying pesticides. I...The tea green leafhopper, Empoasca vitis Gothe, is one of the most serious insect pests of tea plantations in China's Mainland. Over the past decades, this pest has been controlled mainly by spraying pesticides. Insecticide applications not only have become less effective in controlling damage, but even more seriously, have caused high levels of toxic residues in teas, which ultimately threatens human health. Therefore, we should seek a safer biological control approach. In the present study, key components of tea shoot volatiles were identified and behaviorally tested as potential leafhopper attractants. The following 13 volatile compounds were identified from aeration samples of tea shoots using gas chromatography-mass spectrometry （GC-MS）： （E）-2-hexenal, （Z）-3-hexen-1- ol, （Z）-3-hexenyl acetate, 2-ethyl-1-hexanol, （E）-ocimene, linalool, nonanol, （Z）-butanoic acid, 3-hexenyl ester, decanal, tetradecane, β-caryophyllene, geraniol and hexadecane. In Y-tube olfactometer tests, the following individual compounds were identified： （E）-2- hexenal, （E）-ocimene, （Z）-3-hexenyl acetate and linalool, as well as two synthetic mixtures （called blend 1 and blend 2） elicited significant taxis, with blend 2 being the most attractive. Blend 1 included linalool, （Z）-3-hexen-l-ol and （E）-2-hexenal at a 1： 1：1 ratio, whereas blend 2 was a mixture of eight compounds at the same loading ratio： （E）-2-hexenal, （Z）- 3-hexen-l-ol, （Z）-3-hexenyl acetate, 2-penten-l-ol, （E）-2-pentenal, pentanol, hexanol and 1-penten-3-ol. In tea fields, the bud-green sticky board traps baited with blend 2, （E）-2- hexenal or hexane captured adults and nymphs of the leafhoppers, with blend 2 being the most attractive, foUowed by （E）-2-hexenal and hexane. Placing sticky traps baited with blend 2 or （E）-2-hexenal in the tea fields significantly reduced leathopper populations. Our results indicate that the bud-green sticky traps baited with tea shoot volatiles can provide a n展开更多
Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past dec...Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know （or what we think we know） and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation.展开更多
基金This work was partially supported by the National Science Fund for Distinguished Young Scholars (Grant No. 30125032) the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE The work was also sup
文摘Virus isolate Y1 was obtained from tobacco showing curly shoot symptoms in Baoshan, Yunnan Province. Whitefly transmission test and virion morphology observa-tion showed that it is a begomovirus. In reactions with 14 monoclonal antibodies raised against begomoviruses, Y1 was readily differentiated from begomoviruses reported in China, Pakistan and India. The complete nucleotide sequence of DNA-A was determined, it contains 2746 nucleotides, with two ORFs in virion-sense DNA and four ORFs in comple-mentary-sense DNA. Comparisons with total DNA-A, inter-genie region and deduced amino acid sequences of individual ORFs showed that Y1 is a distinct Begomovirus species, for which the name Tobacco curly shoot virus (TCSV) is pro-posed. The total DNA-A of TCSV is most closely related to that of Tomato leaf curl virus from India (85% sequence identity). In contrast, the deduced coat protein of TCSV is most like that of Cotton leaf curl virus 72b isolate from Paki-stan (98% amino acid sequence identity).
文摘Plant hormones regulate many aspects of plant growth and development. Both auxin and cytokinin have been known for a long time to act either synergistically or antagonistically to control several significant developmental processes, such as the formation and maintenance of meristem. Over the past few years, exciting progress has been made to reveal the molecular mechanisms underlying the auxin-cytokinin action and interaction. In this review, we shall briefly discuss the major progress made in auxin and cytokinin biosynthesis, auxin transport, and auxin and cytokinin signaling. The frameworks for the complicated interaction of these two hormones in the control of shoot apical meristem and root apical meristem formation as well as their roles in in vitro organ regeneration are the major focus of this review.
文摘MicroRNAs （miRNAs） are -21-nucleotide noncoding RNAs that play critical roles in regulating plant growth and development through directing the degradation of target mRNAs. Axillary meristem activity, and hence shoot branching, is influenced by a complicated network that involves phytohormones such as auxin, cytokinin, and strigolactone. GAI, RGA, and SCR （GRAS） family members take part in a variety of developmental processes, including axillary bud growth. Here, we show that the Arabidopsis thaliana microRNA171c （miR171c） acts to negatively regulate shoot branching through targeting GRAS gene family members SCARECROW-LIKE6-Ⅱ （SCL6-Ⅱ）, SCL6-Ⅲ, and SCL6-Ⅳ for cleavage. Transgenic plants overexpressing MIR171c （35Spro-MIR171c） and sd6-Ⅱ scl6-Ⅲ scl6-Ⅳ triple mutant plants exhibit a similar reduced shoot branching phenotype. Expression of any one of the miR171c-resistant versions of SCL6-Ⅱ, SCL6-Ⅲ, and SCL6-Ⅳ in 35Spro- MIR171c plants rescues the reduced shoot branching phenotype. Scl6-Ⅱ scl6-Ⅲ scl6-Ⅳ mutant plants exhibit pleiotropic phenotypes such as increased chlorophyll accumulation, decreased primary root elongation, and abnormal leaf and flower patterning. SCL6-Ⅱ, SCL6-Ⅲ, and SCL6-Ⅳ are located to the nucleus, and show transcriptional activation activity. Our results suggest that miR171c-targeted SCL6-Ⅱ, SCL6-Ⅲ, and SCL6-Ⅳ play an important role in the regulation of shoot branch production.
文摘The tea green leafhopper, Empoasca vitis Gothe, is one of the most serious insect pests of tea plantations in China's Mainland. Over the past decades, this pest has been controlled mainly by spraying pesticides. Insecticide applications not only have become less effective in controlling damage, but even more seriously, have caused high levels of toxic residues in teas, which ultimately threatens human health. Therefore, we should seek a safer biological control approach. In the present study, key components of tea shoot volatiles were identified and behaviorally tested as potential leafhopper attractants. The following 13 volatile compounds were identified from aeration samples of tea shoots using gas chromatography-mass spectrometry （GC-MS）： （E）-2-hexenal, （Z）-3-hexen-1- ol, （Z）-3-hexenyl acetate, 2-ethyl-1-hexanol, （E）-ocimene, linalool, nonanol, （Z）-butanoic acid, 3-hexenyl ester, decanal, tetradecane, β-caryophyllene, geraniol and hexadecane. In Y-tube olfactometer tests, the following individual compounds were identified： （E）-2- hexenal, （E）-ocimene, （Z）-3-hexenyl acetate and linalool, as well as two synthetic mixtures （called blend 1 and blend 2） elicited significant taxis, with blend 2 being the most attractive. Blend 1 included linalool, （Z）-3-hexen-l-ol and （E）-2-hexenal at a 1： 1：1 ratio, whereas blend 2 was a mixture of eight compounds at the same loading ratio： （E）-2-hexenal, （Z）- 3-hexen-l-ol, （Z）-3-hexenyl acetate, 2-penten-l-ol, （E）-2-pentenal, pentanol, hexanol and 1-penten-3-ol. In tea fields, the bud-green sticky board traps baited with blend 2, （E）-2- hexenal or hexane captured adults and nymphs of the leafhoppers, with blend 2 being the most attractive, foUowed by （E）-2-hexenal and hexane. Placing sticky traps baited with blend 2 or （E）-2-hexenal in the tea fields significantly reduced leathopper populations. Our results indicate that the bud-green sticky traps baited with tea shoot volatiles can provide a n
基金This work was funded by the National Science Foundation，A.S.M.and Purdue Agriculture Research Foundation grant to W.A.P
文摘Polar transport of the phytohormone auxin and the establishment of localized auxin maxima regulate em- bryonic development, stem cell maintenance, root and shoot architecture, and tropic growth responses. The past decade has been marked by dramatic progress in efforts to elucidate the complex mechanisms by which auxin transport regulates plant growth. As the understanding of auxin transport regulation has been increasingly elaborated, it has become clear that this process is involved in almost all plant growth and environmental responses in some way. However, we still lack information about some basic aspects of this fundamental regulatory mechanism. In this review, we present what we know （or what we think we know） and what we do not know about seven auxin-regulated processes. We discuss the role of auxin transport in gravitropism in primary and lateral roots, phototropism, shoot branching, leaf expansion, and venation. We also discuss the auxin reflux/fountain model at the root tip, flavonoid modulation of auxin transport processes, and outstanding aspects of post-translational regulation of auxin transporters. This discussion is not meant to be exhaustive, but highlights areas in which generally held assumptions require more substantive validation.
