Phytohormone abscisic acid (ABA) was critical for many plant growth and developmental processesincluding seed maturation, germination and response to environmental factors. With the purpose to detectthe possible ABA r...Phytohormone abscisic acid (ABA) was critical for many plant growth and developmental processesincluding seed maturation, germination and response to environmental factors. With the purpose to detectthe possible ABA related signal transduction pathways, we tried to isolate ABA-regulated genes throughcDNA macroarray technology using ABA-treated rice seedling as materials (under treatment for 2, 4, 8 and12 h). Of 6144 cDNA clones tested, 37 differential clones showing induction or suppression for at least onetime, were isolated. Of them 30 and 7 were up- or down-regulated respectively. Sequence analyses revealedthat the putative encoded proteins were involved in different possible processes, including transcription,metabolism and resistance, photosynthesis, signal transduction, and seed maturation. 6 cDNA clones werefound to encode proteins with unknown functions. Regulation by ABA of 7 selected clones relating to signaltransduction or metabolism was confirmed by reverse transcription PCR. In addition, some clones werefurther shown to be regulated by other plant growth regulators including auxin and brassinosteroid, which,however, indicated the complicated interactions of plant hormones. Possible signal transduction pathwaysinvolved in ABA were discussed.展开更多
It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth...It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth. To elucidate whether plant hormones are involved in these processes, the effects of exogenous phytohormones, indole-3-acetic acid （IAA）, abscisic acid （ABA）, gibberellin A3 （GA3） and cytokinin （kinetin） on the growth, PM polarization, actin cytoskeleton （AC） organization and cytoplasmic pH （pile） of in vitro 4 h-growing petunia pollen tubes were investigated. IAA, ABA and GA3 displayed the growth-stimulating effects and these were accompanied by orthovanadate-sensitive hyperpolarization of the PM. Fluorescent labeling the enzyme with H＋-ATPase antibodies exhibited IAA- and ABA-induced lateral PM redistribution of it into the subapical zone of pollen tube PM. Pollen cultivation on the medium with latrunculin B, the inhibitor of actin polymerization, resulted in inhibition of pollen tube growth and simultaneously in the drop of endogenous IAA content. The IAA-growth stimulating effect was correlated with increased content of actin filaments （AF） in both apical and subapical zones of tubes, while ABA and GA3 exerted the same effect but it was accompanied by redistributing F-actin only to apical zone. In contrast, kinetin decreased the total F-actin content and inhibited pollen tube growth. It has been shown that the pHe of growing pollen tubes is sensitive to the plant hormones. In the case of male gametophyte growing for 1, 2 and 4 h, IAA induced alkalinization of the cytosol, while ABA and GA3 exerted qualitatively similar effect only after its growth for 1 h and 4 h, respectively. Kinetin, in contrast, resulted in acidification of the cytosol. All these results, taken together, indicate, for the first time, potential targets of the phytohormone action in pollen tubes.展开更多
基金Researches were supported by "the State Key Project of Basic Research, G1999011604" "Key Project of Knowledge Innovation, CAS", "the National Natural Science Foundation of China, No.30070073" "National Sciences Foundation of Pan-Deng". We thank Prof.
文摘Phytohormone abscisic acid (ABA) was critical for many plant growth and developmental processesincluding seed maturation, germination and response to environmental factors. With the purpose to detectthe possible ABA related signal transduction pathways, we tried to isolate ABA-regulated genes throughcDNA macroarray technology using ABA-treated rice seedling as materials (under treatment for 2, 4, 8 and12 h). Of 6144 cDNA clones tested, 37 differential clones showing induction or suppression for at least onetime, were isolated. Of them 30 and 7 were up- or down-regulated respectively. Sequence analyses revealedthat the putative encoded proteins were involved in different possible processes, including transcription,metabolism and resistance, photosynthesis, signal transduction, and seed maturation. 6 cDNA clones werefound to encode proteins with unknown functions. Regulation by ABA of 7 selected clones relating to signaltransduction or metabolism was confirmed by reverse transcription PCR. In addition, some clones werefurther shown to be regulated by other plant growth regulators including auxin and brassinosteroid, which,however, indicated the complicated interactions of plant hormones. Possible signal transduction pathwaysinvolved in ABA were discussed.
文摘It is known that cytoskeleton-dependent trafficking of cell wall and membrane components to apical plasma membrane （PM） coupled with ion transport across pollen PM is crucial for maintaining polar pollen tube growth. To elucidate whether plant hormones are involved in these processes, the effects of exogenous phytohormones, indole-3-acetic acid （IAA）, abscisic acid （ABA）, gibberellin A3 （GA3） and cytokinin （kinetin） on the growth, PM polarization, actin cytoskeleton （AC） organization and cytoplasmic pH （pile） of in vitro 4 h-growing petunia pollen tubes were investigated. IAA, ABA and GA3 displayed the growth-stimulating effects and these were accompanied by orthovanadate-sensitive hyperpolarization of the PM. Fluorescent labeling the enzyme with H＋-ATPase antibodies exhibited IAA- and ABA-induced lateral PM redistribution of it into the subapical zone of pollen tube PM. Pollen cultivation on the medium with latrunculin B, the inhibitor of actin polymerization, resulted in inhibition of pollen tube growth and simultaneously in the drop of endogenous IAA content. The IAA-growth stimulating effect was correlated with increased content of actin filaments （AF） in both apical and subapical zones of tubes, while ABA and GA3 exerted the same effect but it was accompanied by redistributing F-actin only to apical zone. In contrast, kinetin decreased the total F-actin content and inhibited pollen tube growth. It has been shown that the pHe of growing pollen tubes is sensitive to the plant hormones. In the case of male gametophyte growing for 1, 2 and 4 h, IAA induced alkalinization of the cytosol, while ABA and GA3 exerted qualitatively similar effect only after its growth for 1 h and 4 h, respectively. Kinetin, in contrast, resulted in acidification of the cytosol. All these results, taken together, indicate, for the first time, potential targets of the phytohormone action in pollen tubes.
