Project description:Rhododendron is well known woody plant, as having high ornamental and economic values. Heat stress is one of the important environmental stresses that effects Rhododendron growth. Recently, melatonin was reported to alleviate abiotic stress in plants. However, the role of melatonin in Rhododendron is still unknown. In the present study, the effect of melatonin on Rhododendron under heat stress and the potential mechanism was investigated. Through morphological characterization and chlorophyll a fluorescence analysis, 200µM was selected for the best melatonin concentration to mitigate heat stress in Rhododendron. To reveal the mechanism of melatonin priming alleviating the heat stress, the photosynthesis indexes, Rubisco activity and ATP content were detected in 25 ℃, 35 ℃ and 40 ℃. The results showed that melatonin improves electron transport rate (ETR), PSII and PSI activity, Rubisco activity and ATP content under high temperature stress. Furthermore, transcriptome analysis showed that a significant enrichment of differentially expressed genes in the photosynthesis pathway, and most of genes in photosynthesis pathway displayed a more significantly slight down-regulation under high temperature stress in melatonin-treatment plants, compared with melatonin-free plants. We identified PGR5……Together, these results demonstrate that melatonin could promote the photosynthetic electron transport, improve the enzymes activities in Calvin cycle and the production of ATP, and thereby increase photosynthetic efficiency and CO2 assimilation capacity under heat stress, through regulating the expression of some key genes, such as PGR5…Therefore, melatonin application displayed great potential to cope with the heat stress in Rhododendron.
Project description:Oilseed rape is both an important oleaginous crop and agriculture sightseeing crop whereas has relatively scanty flower color. As natural flavonoids, Anthocyanin are responsible for the attractive red, purple, and blue colors of various tissues in higher plants, especially for the ornamental plants flower. One Brassica napus-Orychophragmus violaceus disomic addition line (M4) obtained previously exhibits red petals whichresult from anthocyanin biosynthesis. Transcriptome analysis of M4, B. napus (H3), natural individuals of O. violaceus with purple petals (OvP) and white petals (OvW) revealed that most of structural genes for the anthocyanin synthesis were up-regulated in both M4 and OvP, especially key gene ANS in the last step. Reads assembling and sequence alignment showed that the regulatory DEG PAP2 in M4 was from the transcript of O. violaceus. OvPAP2 was transformed into Arabidopsis thaliana and B. napus driven by the CaMV35S promoter and the rape petal-specific prompter XY355. Transgenic A. thaliana plants showed different levels of purple pigments in most of the organs, including the petals, and transgenic B. napus flowers exhibited restricted accumulation of anthocyanins in stamens when driven by CaMV35S promoter, but generated both red petals and anthers driven by the XY355 promoter. These results provided a platform for expounding the anthocyanin biosynthesis pathway in B. napus petals and give a successful case for flower color modification of the agriculture sightseeing rape.
2017-12-30 | GSE93089 | GEO
Project description:Transcriptomic analysis of Rhododendron species
Project description:TCP transcription factors from the CYC2-class are involved in the development of monosymmetric flowers in all core eudicot species analysed so far. In Antirrhinum majus, the CYC2/TCP transcription factor CYCLOIDEA (CYC) is the molecular key regulator driving the development of flower monosymmetry (Luo D, Carpenter R, Vincent C, Copsey L, Coen E: Origin of floral asymmetry in Antirrhinum. Nature 1996, 383:794-799). In the Brassicaceae Iberis amara, a stronger expression of the CYC2 gene IaTCP1 in the small adaxial petals likely leads to the reduced petal size in comparison to large abaxial petals, with hardly any IaTCP1 expression. This results in the formation of the monosymmetric Iberis flower (Busch A, Zachgo S: Control of corolla monosymmetry in the Brassicaceae Iberis amara. PNAS 2007, 104:16714-16719). In contrast, the orthologous TCP/CYC2 transcription factor TCP1 from Arabidopsis thaliana, which forms equally sized and shaped petal pairs, only shows an early and transient expression in the adaxial area of floral primordia. This implies that monosymmetry in the Brassicaceae evolved through a heterochronic expression shift of the TCP/CYC2 key regulator gene IaTCP1. Transgenic Arabidopsis plants overexpressing IaTCP1 and TCP1 develop smaller petals whereas transgenic plants overexpressing CYC from Antirrhinum majus produce larger flowers. In any case, petal size is affected. To compare the effects of the three CYC2 TCP transcription factors on downstream (regulatory) networks in Arabidopsis thaliana, a microarray analysis was conducted.
2014-10-14 | GSE62213 | GEO
Project description:Transcriptomes of single and double petals of Rhododendron agastum
Project description:TCP transcription factors from the CYC2-class are involved in the development of monosymmetric flowers in all core eudicot species analysed so far. In Antirrhinum majus, the CYC2/TCP transcription factor CYCLOIDEA (CYC) is the molecular key regulator driving the development of flower monosymmetry (Luo D, Carpenter R, Vincent C, Copsey L, Coen E: Origin of floral asymmetry in Antirrhinum. Nature 1996, 383:794-799). In the Brassicaceae Iberis amara, a stronger expression of the CYC2 gene IaTCP1 in the small adaxial petals likely leads to the reduced petal size in comparison to large abaxial petals, with hardly any IaTCP1 expression. This results in the formation of the monosymmetric Iberis flower (Busch A, Zachgo S: Control of corolla monosymmetry in the Brassicaceae Iberis amara. PNAS 2007, 104:16714-16719). In contrast, the orthologous TCP/CYC2 transcription factor TCP1 from Arabidopsis thaliana, which forms equally sized and shaped petal pairs, only shows an early and transient expression in the adaxial area of floral primordia. This implies that monosymmetry in the Brassicaceae evolved through a heterochronic expression shift of the TCP/CYC2 key regulator gene IaTCP1. Transgenic Arabidopsis plants overexpressing IaTCP1 and TCP1 develop smaller petals whereas transgenic plants overexpressing CYC from Antirrhinum majus produce larger flowers. In any case, petal size is affected. To compare the effects of the three CYC2 TCP transcription factors on downstream (regulatory) networks in Arabidopsis thaliana, a microarray analysis was conducted. The coding sequences of the TCP/CYC2 transcription factors IaTCP1, TCP1 and CYC were cloned into the pBAR vector (GenBank: AJ251014), resulting in the constructs #0522 (IaTCP1), #0569 (TCP1) and #0577 (CYC). In pBAR, all genes are under the control of the CaMV35S-promoter. Arabidopsis plants were transformed (via floral dip) with respective constructs and also with the empty vector (pBar). Transgenic plants (T1) with petal size deviation from the control (plants transformed with the empty vector and wild type) were selfed and resulting T2 lines with petal size deviations from control were selected. Inflorescence buds from secondary inflorescences were harvested from transgenic T2 plants that formed smaller (#0255 or #0569) or larger (#0577) petals in the main inflorescence. Total RNA was isolated and sent to the Integrated Functional Genomics Service at the University of Münster, Germany, which carried out probe preparation, hybridization and statistical analysis of the data. Differential gene expression was always determined from a comparison of gene expression from #0522, #0569 and #0577, respectively, against the control (#pBar; inflorescence gene expression in plants transformed with an empty vector).
Project description:Investigation of genome-wide gene expression in sepals, petals, stamens, staminodia and carpels in pre-anthesis Aquilegia flowers. One goal was to identify transcriptional signatures associated with petaloidy by comparing gene expression in petals and petaloid sepals. Other goals were to study the evolutionary origin and ecological function of staminodia by comparing a) expression patterns in stamens, staminodia and carpels, b) identifying transcriptional regulators expressed in staminodia and c) using gene set enrichment analysis to identify biological processes operating in staminodia.
Project description:To identify the regulatory steps that control chlorophyll accumulation, we compared gene expression in petals and leaves of chrysanthemum cultivars with different chlorophyll levels. Microarray analyses showed that the expression levels of chlorophyll biosynthesis genes encoding glutamyl-tRNA reductase, Mg-protoporphyrin IX chelatase, Mg-protoporphyrin IX monomethylester cyclase, and protochlorophyllorophyllide oxidoreductase were well associated with chlorophyll content: their expression levels were lower in white petals than in green petals, and were highest in leaves. Among chlorophyll catabolic genes, expression of STAY-GREEN, encoding Mg-dechelatase, which is a key enzyme controlling chlorophyll degradation, was considerably higher in white and green petals than in leaves. We searched for transcription factor genes whose expression was well related to chlorophyll level in petals and leaves and found several such genes.