Petal abscission in rose (Rosa bourboniana var Gruss an Teplitz) is associated with the enhanced expression of an alpha expansin gene, RbEXPA1

Cell Wall Extensibility and Effect of Cell-Wall-Loosening Proteins during Rose Flower Opening

“…These results suggest that petal expansion at stage V occurs across the upper and middle parts of petals, and that RhEXPA1 and RhXTH1 may have important roles in rapid cell expansion. Sane et al (2007) cloned RbEXPA1 from the rose Rosa bourboniana. This clone has 98% identity to our Fig.…”

“…They are commonly identified in expanding and growing tissues. Expansins are also expressed in non-growing tissue, such as in ripening fruits (Brummel et al, 1999;Civello et al, 1999;Rose et al, 1997) and the abscission zone (Belfield et al, 2005;Sane et al, 2007).…”

Expression of mRNAs and Proteins Associated with Cell-wall-loosening during Eustoma Flower Opening

“…In the early stages when EgEXPA1-3 and EgXTH1 showed little expression, petal growth is thought to occur according to the changes in petal size and fresh weight without any petal extensibility change. There are some reports that some expansin and XTH genes were expressed in the abscission zone of petals when flowers senesced (Sane et al, 2007;Singh et al, 2011); however, the transcription levels of EgEXPA1-3 and EgXTH1 kept decreasing after stage V when the flowers continued opening. Thus, they might not be involved in petal growth in bud stages or petal senescence.…”

“…Their genes belong to a multigene family, and two families recognized as α-and β-expansin are commonly identified from expanding and growing tissues (Cosgrove, 2001). Expansin expression has been reported in several ripening fruits (Brummel et al, 1999;Civello et al, 1999;Rose et al, 1997) and the abscission zone (Belfield et al, 2005;Sane et al, 2007).…”

“…In petals, expansins and XTHs have been identified in several species (Gookin et al, 2003;Harada et al, 2010;Takahashi et al, 2007), and the function of α-expansin was analyzed using a transgenic antisense approach in Petunia hybrida (Zenoni et al, 2004). The predominance of XTH activity was associated with the opening of sandersonia flowers (O'Donoghue et al, 2002) and carnation flowers (Harada et al, 2010); however, there are few reports of the protein levels of expansin and XTH during flower opening, although their mRNA expression patterns have been a focus in previous reports (Sane et al, 2007;Singh et al, 2011;Yamada et al, 2009). Eustoma has wide variety of flower color, size, and shape.…”