The ability to adjust growth and development to the availability of mineral nutrients in the soil is an essential life skill of plants but the underlying signaling pathways are poorly understood. In Arab/dops/s thal/a...The ability to adjust growth and development to the availability of mineral nutrients in the soil is an essential life skill of plants but the underlying signaling pathways are poorly understood. In Arab/dops/s thal/ana, shortage of po- tassium （K） induces a number of genes related to the phytohormone jasmonic acid （JA）. Using comparative microarray analysis of wild-type and coi1-16 mutant plants, we classified transcriptional responses to K with respect to their depen- dence on COI1, a central component of oxylipin signaling. Expression profiles obtained in a short-term experiment clearly distinguished between COil-dependent and COil-independent K-responsive genes, and identified both known and novel targets of JA-COIl-signaling. During long-term K-deficiency, coi-16 mutants displayed de novo responses covering similar functions as COil-targets except for defense. A putative role of JA for enhancing the defense potential of K-deficient plants was further supported by the observation that plants grown on low K were less damaged by thrips than plants grown with sufficient K.展开更多
Several herbivorous insects and plant-associated microorganisms control the phytohormonal balance, thus enabling them to successfully exploit the plant by inhibiting plant defenses and withdrawing plant resources for ...Several herbivorous insects and plant-associated microorganisms control the phytohormonal balance, thus enabling them to successfully exploit the plant by inhibiting plant defenses and withdrawing plant resources for their own benefit. The leaf-mining moth Phyllonorycter blancardella modifies the cytokinin （CK） profile of mined leaf-tissues, and the insect symbiotic bacteria Wolbachia is involved in the plant manipulation to the benefit of the insect host. To gain a deeper understanding into the possible origin and dynamics of CKs, we conducted an extensive characterization of CKs in larvae and in infected apple leaves. Our results show the enhanced CK levels in mines, both on green and yellow leaves, allowing insects to control their nutritional supply under fluctuating environmental conditions. The spatial distribution of CKs within the mined leaves shows that hormone manipulation is strictly limited to the mine suggesting the absence of CK translocation from distant leaf areas toward the insect feeding site. Mass spectrometry analyses reveal that major CK types accumulating in mines and larvae are similar to what is observed for most gall-inducers, suggesting that strategies underlying the plant manipulation may be shared between herbivorous insects with distinct life histories. Results further show that CKs are detected in the highest levels in larvae, reinforcing our hypothesis that CKs accumulating in the mines originate from the insect itself. Presence of bacteria- specific methylthio-CKs is consistent with previous results suggesting that insect bacterial symbionts contribute to the observed phenotype. Our study provides key findings toward the understanding of molecular mechanisms underlying this intricate plant-insect-microbe interaction.展开更多
文摘The ability to adjust growth and development to the availability of mineral nutrients in the soil is an essential life skill of plants but the underlying signaling pathways are poorly understood. In Arab/dops/s thal/ana, shortage of po- tassium （K） induces a number of genes related to the phytohormone jasmonic acid （JA）. Using comparative microarray analysis of wild-type and coi1-16 mutant plants, we classified transcriptional responses to K with respect to their depen- dence on COI1, a central component of oxylipin signaling. Expression profiles obtained in a short-term experiment clearly distinguished between COil-dependent and COil-independent K-responsive genes, and identified both known and novel targets of JA-COIl-signaling. During long-term K-deficiency, coi-16 mutants displayed de novo responses covering similar functions as COil-targets except for defense. A putative role of JA for enhancing the defense potential of K-deficient plants was further supported by the observation that plants grown on low K were less damaged by thrips than plants grown with sufficient K.
文摘Several herbivorous insects and plant-associated microorganisms control the phytohormonal balance, thus enabling them to successfully exploit the plant by inhibiting plant defenses and withdrawing plant resources for their own benefit. The leaf-mining moth Phyllonorycter blancardella modifies the cytokinin （CK） profile of mined leaf-tissues, and the insect symbiotic bacteria Wolbachia is involved in the plant manipulation to the benefit of the insect host. To gain a deeper understanding into the possible origin and dynamics of CKs, we conducted an extensive characterization of CKs in larvae and in infected apple leaves. Our results show the enhanced CK levels in mines, both on green and yellow leaves, allowing insects to control their nutritional supply under fluctuating environmental conditions. The spatial distribution of CKs within the mined leaves shows that hormone manipulation is strictly limited to the mine suggesting the absence of CK translocation from distant leaf areas toward the insect feeding site. Mass spectrometry analyses reveal that major CK types accumulating in mines and larvae are similar to what is observed for most gall-inducers, suggesting that strategies underlying the plant manipulation may be shared between herbivorous insects with distinct life histories. Results further show that CKs are detected in the highest levels in larvae, reinforcing our hypothesis that CKs accumulating in the mines originate from the insect itself. Presence of bacteria- specific methylthio-CKs is consistent with previous results suggesting that insect bacterial symbionts contribute to the observed phenotype. Our study provides key findings toward the understanding of molecular mechanisms underlying this intricate plant-insect-microbe interaction.
