Abstract
Due to increased global warming and climate change, drought has become a serious threat to horticultural crop cultivation and management. The purpose of this study was to investigate the effect of spermine (Spm) pretreatment on metabolic alterations of polyamine (PAs), γ-aminobutyric acid (GABA), proline (Pro), and nitrogen associated with drought tolerance in creeping bentgrass (Agrostis stolonifera). The results showed that drought tolerance of creeping bentgrass could be significantly improved by the Spm pretreatment, as demonstrated by the maintenance of less chlorophyll loss and higher photosynthesis, gas exchange, water use efficiency, and cell membrane stability. The Spm pretreatment further increased drought-induced accumulation of endogenous PAs, putrescine, spermidine, and Spm, and also enhanced PAs metabolism through improving arginine decarboxylases, ornithine decarboxylase, S-adenosylmethionine decarboxylase, and polyamine oxidase activities during drought stress. In addition, the Spm application not only significantly improved endogenous GABA content, glutamate content, activities of glutamate decarboxylase and α-ketoglutarase, but also alleviated decline in nitrite nitrogen content, nitrate reductase, glutamine synthetase, glutamate synthetase, and GABA aminotransferase activities under drought stress. The Spm-pretreated creeping bentgrass exhibited significantly lower ammonia nitrogen content and nitrite reductase activity as well as higher glutamate dehydrogenase activity than non-pretreated plants in response to drought stress. These results indicated beneficial roles of the Spm on regulating GABA and nitrogen metabolism contributing towards better maintenance of Tricarboxylic acid (TCA) cycle in creeping bentgrass. Interestingly, the Spm-enhanced Pro metabolism rather than more Pro accumulation could be the key regulatory mechanism for drought tolerance in creeping bentgrass. Current findings provide a comprehensive understanding of PAs interaction with other metabolic pathways to regulate drought tolerance in grass species.
Highlights
Due to the increase in global greenhouse gases and ozone layer depletion over the last few years, extreme weather conditions such as continuous seasonal drought have brought severe challenges for the cultivation and management of crops worldwide
These results indicated that Spm regulated the tolerance against drought stress in plants by inducing a variety of changes in stress pathways
The Put, 5Sopfd17, Spm, or PAs content in leaves of plants pretreated with the Spm increased by 42%, 77%, 122%, or 48% than that in leaves of plants without the Spm pretreatment on the 18th d of dstrroeussg,hrtesssptercetsisv,erleysp(Feicgtuivrel3yA(F–iDg)u.rAes3tAim–De )o.fAdsrotiumgehtofstdrerossuwghetnsttorens,sthweeAntDoCn,OthDeCA,DanCd, OS-DACM, DanCdaSc-tAivMitiDesCgaracdtiuviatlileys ignrcardeausaeldlyinintchrea“sDed” ainndth“eD“D+ ”Spamnd” “trDea+tmSpenmt”
Summary
Due to the increase in global greenhouse gases and ozone layer depletion over the last few years, extreme weather conditions such as continuous seasonal drought have brought severe challenges for the cultivation and management of crops worldwide. Plants have developed a certain degree of self-resistance to adapt the changing environmental conditions at phenotypic, physiological, metabolic, and molecular levels [6]. Plants can regulate the accumulation of Put, Spd, and Spm to enhance the tolerance to salt, drought, and cold stress [10,11]. It has been found that PAs content in cold-tolerant cucumber (Cucumis sativus) cultivar increased greatly, while cold-sensitive cultivar remained unchanged under low temperature stress [12]. The Spm pretreatment could reverse the drought-sensitive phenotype of Arabidopsis acl5/Spms mutant that was unable to produce the Spm [17]. These results indicated that Spm regulated the tolerance against drought stress in plants by inducing a variety of changes in stress pathways
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
