Expression of α-Expansin and Xyloglucan Endotransglucosylase/Hydrolase Genes Associated with Shoot Elongation Enhanced by Anoxia, Ethylene and Carbon Dioxide in Arrowhead (Sagittaria pygmaea Miq.) Tubers

Abstract

In air, promotion by 5% CO2 and 5 microL L-1 ethylene of shoot elongation occurred. At 1% O2, ethylene also stimulated shoot elongation but CO2 did not. Pyrazol inhibited shoot elongation in hypoxia but not in normoxia, suggesting that alcohol fermentation contributes to elongation enhanced by hypoxia. AVG and 1-MCP partially prevented shoot elongation both in normoxia and in hypoxia, but they did not have significant effects in anoxia, suggesting that endogenous ethylene acts as a stimulator of shoot elongation in normoxia and in hypoxia but not in anoxia. Ethylene is not involved in anoxia-enhanced elongation. We cloned four cDNAs (SpEXPA1, 2, 3 and 4) encoding alpha-expansin (EXPA) and five cDNAs (SpXTH1, 2, 3, 4 and 5) encoding xyloglucan endotransglucosylase/hydrolase (XTH) from shoots of arrowhead tubers. The transcript levels of SpEXPA1 and 2 were increased by anoxia and those of SpEXPA2 were increased by 5% CO2. Ethylene slightly elevated the level of SpEXPA4 transcripts. Anoxia enhanced the transcript levels of SpXTH1 and 4; neither ethylene nor CO2 had any effect. CO2 enhanced transcript levels of SpXTH3 and depressed those of SpXTH5. Ethylene decreased transcript levels of SpXTH5. These results suggest that four SpEXPA genes and five SpXTH genes are differently responsive to anoxia, CO2 and ethylene. Enhancement of SpEXPA1 and 2, and SpXTH1 and 4 transcript levels suggests that these gene products are involved in anoxic shoot elongation through modification of cell wall architecture.

Differential expression and regulation of expansin gene family members during fruit growth and development of ‘Shijia’ longan fruit

“…In contrast, DlExp1 and DlExp2 genes were highly expressed in the young stems and young leaves, suggesting that DlExp1 and DlExp2, whose expression might be closely related to the growth of longan fruit, were also correlated with vegetative growth of 'Shijia' longan. These results were consistent with previous reports that high accumulation of Exp mRNA was associated with rapid growth tissues (Li et al 2003;Ookawara et al 2005). DlExp3 expression was not detected in the fruit of 'Shijia' longan while the levels of DlExp3 mRNA were very high in the young leaves of 'Shijia' longan but not in the fully expanded leaves, implying DlExp3 might be responsible for leaf growth in 'Shijia' longan.…”

Anoxia-enhanced expression of genes isolated by suppression subtractive hybridization from pondweed (Potamogeton distinctus A. Benn.) turions

“…In addition to interactions between plant hormones, expression of expansin genes has been suggested to be important for rapid elongation of deepwater rice internodes (Cho and Kende 1997) and shoots of Rumex palustris (Vriezen et al 2000). Moreover, expression of some genes encoding expansin and xyloglucan endotransglucosylase/ hydrolase is up-regulated when shoots of arrowhead tubers elongate in response to anoxic conditions (Ookawara et al 2005). These studies suggest that cell elongation induced in response to low oxygen is regulated by transcription of genes for cell wall modiWcation.…”

Genome histories clarify evolution of the expansin superfamily: new insights from the poplar genome and pine ESTs

“…In the case of LeEXPA10 and RaEXPA4, trees cannot resolve if they belong to clade EXPA-II or EXPA-I. SpEXPA2 appears to belong to a lineage not present in the known angiosperm genomes b Species and references: Car: Cicer arietinum (Sanchez et al 2004), Cpl: Craterostigma plantagineum (Jones and McQueen-Mason 2004), Csa: Cucumis sativus (Shcherban et al 1995;Link et al 2001), Fan: Fragaria ananassa (Civello et al 1999;Harrison et al 2001;Rose et al 1997), Fpa: Festuca pratensis (Reidy et al 2001), Ghi: Gossypium hirsutum (Harmer et al 2002), Gma: Glycine max (Crowell 1994;Lee et al 2003), Les: Lycopersicon esculentum (Rose et al 1997;Reinhardt et al 1998;Brummell et al 1999;Catala et al 2000;Chen and Bradford 2000;Vogler et al 2003), Mac: Musa acuminata (Trivedi and Nath 2004), Mal: Melilotus alba (Giordano and Hirsch 2004), Mdo: Malus × domestica (Wakasa et al 2003), Mja: Mirabilis jalapa (Gookin et al 2003), Nta: Nicotiana tabacum (Link and Cosgrove 1998;Pezzotti et al 2002), Pco: Pyrus communis (Hiwasa et al 2003), Phy: Petunia × hybrida (Zenoni et al 2004), Psa: Pisum sativum (Michael 1996), Rac: Rumex acetosa (Vriezen et al 2000), Rpa: Rumex palustris (Vriezen et al 2000;Colmer et al 2004), Sas: Striga asiatica (O'Malley and Lynn 2000), Sni: Sambucus nigra (Belfield et al 2005), Spy: Sagittaria pygmaea (Ookawara et al 2005), Tve: Triphysaria versicolor (Wrobel and Yoder 2001), Zel: Zinnia elegans (Im et al 2000), Zma: Zea mays (Wu et al 2001;L...…”