biologia plantarum

Biologia plantarum 57:193-198, 2013 | DOI: 10.1007/s10535-012-0266-0

Aquaporin expression during seed osmopriming and post-priming germination in spinach

K. Chen¹, A. Fessehaie², R. Arora^1,*

¹ Department of Horticulture, Iowa State University, Ames, USA

² Seed Science Center, Iowa State University, Ames, USA

Aquaporins (AQPs) are proteinaceous channels known to regulate transmembrane water transport, and therefore may be important component of imbibition during osmopriming and germination. To explore the association between AQPs and osmopriming-led enhanced germination performance, we studied the expression patterns of four spinach (Spinacia oleracea) AQP coding genes (SoPIP1;1, SoPIP1;2, SoPIP2;1, and SoδTIP) during osmopriming and subsequent germination under optimal conditions, chilling and drought. All these genes were up-regulated within 2-4 d of priming (phase II-imbibition). We hypothesize such up-regulation to facilitate the pressure potential-driven cell expansion and increase germination potential of primed seeds. Our data during post-priming germination suggest that SoPIP1;1 and SoδTIP were more closely associated with enhanced germination performance. In general, all AQPs were downregulated under chilling and drought. However, under chilling, SoPIP2;1 was expressed at relatively higher level in primed seeds that also exhibited greater chilling tolerance, while SoPIP1;2 and SoδTIP exhibited opposite pattern. Similarly, SoPIP1;1, SoPIP2;1, and SoδTIP exhibited higher expression in primed seeds that also had greater drought tolerance.

Keywords: chilling; drought; plasma membrane intrinsic protein; polyethylene glycol; tonoplast intrinsic protein

Subjects: aquaporin; osmopriming; germination; temperature low; water stress; plasma membrane intrinsic protein; tonoplast intrinsic protein; polyethylene glycol; spinach

Received: March 15, 2012; Accepted: May 30, 2012; Published: March 1, 2013  Show citation