TY - JOUR
T1 - Molecular and physiological dissection of enhanced seed germination using short-term low-concentration salt seed priming in tomato
AU - Nakaune, Makoto
AU - Hanada, Atsushi
AU - Yin, Yong Gen
AU - Matsukura, Chiaki
AU - Yamaguchi, Shinjiro
AU - Ezura, Hiroshi
N1 - Funding Information:
This work was supported in part by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (No. 21580075 ).
PY - 2012/3
Y1 - 2012/3
N2 - Seed germination is the initial step of plant development. Seed priming with salt promotes seed germination in tomato (Solanum lycopersicum L.); however, the molecular and physiological mechanisms underlying the enhancement of seed germination by priming remain to be elucidated. In this study, we examined the following in seeds both during and after priming treatment: the endogenous abscisic acid (ABA) and gibberellin (GA) concentrations; the expression of genes encoding ABA catabolic and GA biosynthesis enzymes, including 8'-hydroxylase (CYP707A), copalyl diphosphate synthase (CPS), GA 20-oxidase (GA20ox) and GA 3-oxidase (GA3ox); and endosperm cap weakening enzymes, including expansin (EXP), class I β-1,3-glucanase (GulB), endo-β-mannanase (MAN) and xyloglucan endotransglucosylase (XTH). Tomato seeds were soaked for 24h at 25°C in the dark in 300mM NaCl (NaCl-priming) or distilled water (hydro-priming). For both priming treatments, the ABA content in the seeds increased during treatment but rapidly decreased after sowing. Both during and after the priming treatments, the ABA levels in the hydro-primed seeds and NaCl-primed seeds were not significantly different. The expression levels of SlGA20ox1, SlGA3ox1 and SlGA3ox2 were significantly enhanced in the NaCl-primed seeds compared to the hydro-primed seeds. The GA4 content was quantifiable after both types of priming, indicating that GA4 is the major bioactive GA molecule involved in tomato seed germination. The GA4 content was significantly higher in the NaCl-primed seeds than in the hydro-primed seeds 12h after sowing and thereafter. Additionally, the peak expression levels of SlEXP4, SlGulB, SlMAN2 and SlXTH4 occurred earlier and were significantly higher in the NaCl-primed seeds than in the hydro-primed seeds. These results suggest that the observed effect of NaCl-priming on tomato seed germination is caused by an increase of the GA4 content via GA biosynthetic gene activation and a subsequent increase in the expression of genes related to endosperm cap weakening.
AB - Seed germination is the initial step of plant development. Seed priming with salt promotes seed germination in tomato (Solanum lycopersicum L.); however, the molecular and physiological mechanisms underlying the enhancement of seed germination by priming remain to be elucidated. In this study, we examined the following in seeds both during and after priming treatment: the endogenous abscisic acid (ABA) and gibberellin (GA) concentrations; the expression of genes encoding ABA catabolic and GA biosynthesis enzymes, including 8'-hydroxylase (CYP707A), copalyl diphosphate synthase (CPS), GA 20-oxidase (GA20ox) and GA 3-oxidase (GA3ox); and endosperm cap weakening enzymes, including expansin (EXP), class I β-1,3-glucanase (GulB), endo-β-mannanase (MAN) and xyloglucan endotransglucosylase (XTH). Tomato seeds were soaked for 24h at 25°C in the dark in 300mM NaCl (NaCl-priming) or distilled water (hydro-priming). For both priming treatments, the ABA content in the seeds increased during treatment but rapidly decreased after sowing. Both during and after the priming treatments, the ABA levels in the hydro-primed seeds and NaCl-primed seeds were not significantly different. The expression levels of SlGA20ox1, SlGA3ox1 and SlGA3ox2 were significantly enhanced in the NaCl-primed seeds compared to the hydro-primed seeds. The GA4 content was quantifiable after both types of priming, indicating that GA4 is the major bioactive GA molecule involved in tomato seed germination. The GA4 content was significantly higher in the NaCl-primed seeds than in the hydro-primed seeds 12h after sowing and thereafter. Additionally, the peak expression levels of SlEXP4, SlGulB, SlMAN2 and SlXTH4 occurred earlier and were significantly higher in the NaCl-primed seeds than in the hydro-primed seeds. These results suggest that the observed effect of NaCl-priming on tomato seed germination is caused by an increase of the GA4 content via GA biosynthetic gene activation and a subsequent increase in the expression of genes related to endosperm cap weakening.
KW - Abscisic acid
KW - GA 3-oxidase
KW - Gibberellin
KW - Salt
KW - Seed priming
KW - Tomato
UR - http://www.scopus.com/inward/record.url?scp=83055181989&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=83055181989&partnerID=8YFLogxK
U2 - 10.1016/j.plaphy.2011.11.005
DO - 10.1016/j.plaphy.2011.11.005
M3 - Article
C2 - 22305065
AN - SCOPUS:83055181989
VL - 52
SP - 28
EP - 37
JO - Plant Physiology and Biochemistry
JF - Plant Physiology and Biochemistry
SN - 0981-9428
ER -