Molecular function of Oncidium ascorbate peroxidase on thermal-induced flowering process in Arabidopsis thaliana
Date Issued
2011
Date
2011
Author(s)
Huang, Bo-Ruei
Abstract
Oncidium Gower ramsey is an economically important cutting flower in orchid industry. Mild increase of growth temperature is effective to promote Oncidum flowering, in example of elevating day/night temperature from 25˚C/20˚C to 30˚C /25˚C. Our previous studies have revealed that higher growth temperature also induced the expression of ASCORBATE PEROXIDASE (OgAPX) and resulted in the deprivation of ascorbate (AsA) level. In order to decipher the underlying role of AsA under thermal-regulated flowering, OgAPX was overexpressed in Arabidopsis. There was no significant change on morphology between transgenic and control plants when growing under 22˚C. The OgAPXOE transgenic plants exhibited precocious flowering and reduction of chlorophyll content compared with control when growing at 30˚C condition. Microarray analyses of transgenic and control plants growing at 22˚C condition displayed differential expression patterns of genes to plants growing at 30˚C in categories in oxidoreductase, senescence, defense, signal transduction and transcription factors. AtMYB70, AP2, circadian genes and At3g30720, which displayed up/down-regulated expression pattern under elevated growth temperature condition were further validated by quantitative RT-PCR. Moreover, their expression levels were
10
associated with the endogenous AsA level and displayed up-regulation level in ascorbate-deficient mutant, vtc1, but down-regulated level in ascorbate-accumulated transgenic plants, OgPMEOX. Noteworthy, attenuated expression level of At3g30720 encoding qua-quine starch (QQS) which acting on starch biosynthesis, provides a regulatory function of AsA state on the cross-talk of thermal- and energy-regulated flowering. Taken together, our results bring about a genetic network of flowering mechanism orchestrated by the elevated growth temperature.
Subjects
ascorbate peroxidase
thermal-induced flowering
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-100-R98b42029-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):0f249d69d2e8c9955344eb000ca47025