Žižková E., Dobrev P.I., Muhovski Y., Hošek P., Hoyerová K., Haisel D., Procházková D., Lutts S., Motyka V., Hichri I.
BMC PLANT BIOLOGY
15:
85,
2015
Klíčová slova:
Cytokinin, isopentenyltransferase, salt stress, SlIPT3, SlIPT4, tomato
Abstrakt:
Cytokinins (CKs) are involved in response to various environmental cues, including salinity. It has been
previously reported that enhancing CK contents improved salt stress tolerance in tomato. However, the underlying
mechanisms of CK metabolism and signaling under salt stress conditions remain to be deciphered. Two tomato isopentenyltransferases, SlIPT3 and SlIPT4, were characterized in tomato and Arabidopsis.
Both proteins displayed isopentenyltransferase (IPT) activity in vitro, while their encoding genes exhibited
different spatio-temporal expression patterns during tomato plant development. SlIPT3 and SlIPT4 were affected
by the endogenous CK status, tightly connected with CKs feedback regulation, as revealed by hormonal treatements. In
response to salt stress, SlIPT3 and SlIPT4 were strongly repressed in tomato roots, and differently affected in young and
old leaves. SlIPT3 overexpression in tomato resulted in high accumulation of different CK metabolites, following
modifications of CK biosynthesis-, signaling- and degradation-gene expression. In addition, 35S::SlIPT3 tomato
plants displayed improved tolerance to salinity consecutive to photosynthetic pigments and K+/Na+ ratio retention.
Involvement of SlIPT3 and SlIPT4 in salt stress response was also observed in Arabidopsis ipt3 knock-out complemented
plants, through maintenance of CK homeostasis.
To summarize, SlIPT3 and SlIPT4 are functional IPTs encoded by differently expressed genes, distinctively taking part in
the salinity response. The substantial participation of SlIPT3 in CK metabolism during salt stress has been determined in
35S::SlIPT3 tomato transformants, where enhancement of CKs accumulation significantly improved plant tolerance to
salinity, underlining the importance of this phytohormone in stress response.
Fulltext: kontaktujte autory z ÚEB
Autoři z ÚEB: Petre I. Dobrev,
Daniel Haisel,
Klára Hoyerová,
Václav Motyka,
Dagmar Procházková,
Eva Žižková
Čeština
English