Abstract
Aquaporins are water channel proteins that facilitate the passage of water through biological membranes and play a crucial role in plant growth. We showed that ethylene treatment significantly reduced petal size, inhibited expansion of petal abaxial subepidermal cells, and decreased petal water content in rose (Rosa hybrida 'Samantha'). Here, we report the isolation of a plasma membrane aquaporin (PIP) gene, Rh-PIP2;1, and characterized its potential role in ethylene-inhibited petal expansion. Rh-PIP2;1 is mainly localized on the plasma membrane and belongs to the class 2 subfamily of PIP proteins. We show that Rh-PIP2;1 is an active water channel. The transcripts of Rh-PIP2;1 are highly abundant in petal epidermal cells, especially in the abaxial subepidermal cells. The expression of Rh-PIP2;1 is highly correlated with petal expansion and tightly down-regulated by ethylene. Furthermore, we demonstrate that in Rh-PIP2;1-silenced flowers, petal expansion was greatly inhibited and anatomical features of the petals were similar to those of ethylene-treated flowers. We argue that Rh-PIP2;1 plays an important role in petal cell expansion and that ethylene inhibits petal expansion of roses at least partially by suppressing Rh-PIP2;1 expression.
Highlights
Aquaporins are water channel proteins that facilitate the passage of water through biological membranes and play a crucial role in plant growth
We found that ethylene significantly reduced petal size and water content in roses and inhibited petal expansion by inhibiting cell expansion
Ethylene treatment resulted in interlocking abaxial subepidermis (AbsE) cells of irregular shape, suggesting that normal cell polar expansion might be impeded by ethylene (Fig. 2B). These results indicated that ethylene inhibited petal expansion, at least partially, through the inhibition of AbsE cell expansion
Summary
Effects of ethylene on petal expansion during flower opening. Our results showed that ethylene treatment resulted in vertically compressed flowers with decreased flower height-to-flower diameter ratio in rose (Rosa hybrida ‘Samantha’). Petal growth during flower opening is driven mainly by cell expansion, a process of rapid water uptake. Ethylene treatment substantially decreased the petal fresh weight, while 1-MCP significantly increased the fresh weight. BQ104371) showed approximately 20-fold increase in expression in rose petals during the early period of flower opening, according to a microarray analysis (Guterman et al, 2002) We characterized this EST for its functional role in rose petal expansion. On average, the Pf value of leaf protoplasts in transgenic plants was significantly higher than that in the wild type (14.4 and 6.6, respectively; P , 0.01) After 3 d of flower opening, when the petal expansion process was almost completed (Fig. 6B)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
