Limits...
Tomato (Solanum lycopersicum L.) SlIPT3 and SlIPT4 isopentenyltransferases mediate salt stress response in tomato.

Žižková E, Dobrev PI, Muhovski Y, Hošek P, Hoyerová K, Haisel D, Procházková D, Lutts S, Motyka V, Hichri I - BMC Plant Biol. (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic. zizkovae@ueb.cas.cz.

ABSTRACT

Background: 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.

Results: 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.

Conclusions: 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.

No MeSH data available.


Related in: MedlinePlus

Salinity response of SlIPT3 and SlIPT4 in Arabidopsis. Germination percentage (A) and survival percentage (B) of SlIPT4 (lines 3AT and 5AT) and SlIPT3 (lines 9AT and 10AT) Arabidopsis ipt3 complemented plants. **significantly lower germination and survival percentages compared to ipt3 KO. ***significantly lower survival percentages compared to WT and ipt3 KO. (C) Primary root length of Arabidopsis SlIPT3 and SlIPT4 complemented plants. *significantly longer primary root compared to WT. **significantly shorter primary root compared to WT. ***significantly shorter primary root compared to ipt3 KO plants (Mann–Whitney U Test with p ≤ 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4404076&req=5

Fig4: Salinity response of SlIPT3 and SlIPT4 in Arabidopsis. Germination percentage (A) and survival percentage (B) of SlIPT4 (lines 3AT and 5AT) and SlIPT3 (lines 9AT and 10AT) Arabidopsis ipt3 complemented plants. **significantly lower germination and survival percentages compared to ipt3 KO. ***significantly lower survival percentages compared to WT and ipt3 KO. (C) Primary root length of Arabidopsis SlIPT3 and SlIPT4 complemented plants. *significantly longer primary root compared to WT. **significantly shorter primary root compared to WT. ***significantly shorter primary root compared to ipt3 KO plants (Mann–Whitney U Test with p ≤ 0.05).

Mentions: On the control medium, germination and survival frequencies were not significantly different in between the variants reaching 100%. On the saline medium, seed germination percentage was reduced to 67% for both lines of Arabidopsis SlIPT3 complemented plants (9AT and 10AT lines), significantly less than that of ipt3 KO and WT plants (Figure 4A). However, in Arabidopsis SlIPT4 complemented plants (3AT and 5AT lines), seed germination reached 89% and 90%, respectively, while WT seeds displayed 78% and ipt3 KO 93% of germination rate, respectively. The same trend was detected for seedlings’ survival percentage on 100 mM NaCl (Figure 4B) (Fisher’s exact test with p ≤ 0.05). Similarly, primary root elongation was estimated by screening 10 DAS Arabidopsis SlIPT3 and SlIPT4 complemented plants (Figure 4C). On control medium, the primary root length among the 9AT and 10AT lines significantly differed compared to WT while on the salt-containing medium, no significant changes between the SlIPT3 complemented and WT plants were observed. Arabidopsis plants complemented with SlIPT4 showed significantly longer primary root (3.77 ± 0.41 and 3.85 ± 0.8 cm for 3AT and 5AT, respectively) than WT (3.35 ± 0.58 cm) on control medium, while antagonistic effects were detected on salt-containing medium (Figure 4C, Mann–Whitney U Test with p ≤ 0.05). These results demonstrate that both tomato IPT enzymes are functional in heterologous system. However, in reaction to salt stress the SlIPT4 complemented plants displayed the same characteristics as WT in germination and survival assays, while both of the SlIPT3 complemented lines differed in their response to salinity.Figure 4


Tomato (Solanum lycopersicum L.) SlIPT3 and SlIPT4 isopentenyltransferases mediate salt stress response in tomato.

Žižková E, Dobrev PI, Muhovski Y, Hošek P, Hoyerová K, Haisel D, Procházková D, Lutts S, Motyka V, Hichri I - BMC Plant Biol. (2015)

Salinity response of SlIPT3 and SlIPT4 in Arabidopsis. Germination percentage (A) and survival percentage (B) of SlIPT4 (lines 3AT and 5AT) and SlIPT3 (lines 9AT and 10AT) Arabidopsis ipt3 complemented plants. **significantly lower germination and survival percentages compared to ipt3 KO. ***significantly lower survival percentages compared to WT and ipt3 KO. (C) Primary root length of Arabidopsis SlIPT3 and SlIPT4 complemented plants. *significantly longer primary root compared to WT. **significantly shorter primary root compared to WT. ***significantly shorter primary root compared to ipt3 KO plants (Mann–Whitney U Test with p ≤ 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4404076&req=5

Fig4: Salinity response of SlIPT3 and SlIPT4 in Arabidopsis. Germination percentage (A) and survival percentage (B) of SlIPT4 (lines 3AT and 5AT) and SlIPT3 (lines 9AT and 10AT) Arabidopsis ipt3 complemented plants. **significantly lower germination and survival percentages compared to ipt3 KO. ***significantly lower survival percentages compared to WT and ipt3 KO. (C) Primary root length of Arabidopsis SlIPT3 and SlIPT4 complemented plants. *significantly longer primary root compared to WT. **significantly shorter primary root compared to WT. ***significantly shorter primary root compared to ipt3 KO plants (Mann–Whitney U Test with p ≤ 0.05).
Mentions: On the control medium, germination and survival frequencies were not significantly different in between the variants reaching 100%. On the saline medium, seed germination percentage was reduced to 67% for both lines of Arabidopsis SlIPT3 complemented plants (9AT and 10AT lines), significantly less than that of ipt3 KO and WT plants (Figure 4A). However, in Arabidopsis SlIPT4 complemented plants (3AT and 5AT lines), seed germination reached 89% and 90%, respectively, while WT seeds displayed 78% and ipt3 KO 93% of germination rate, respectively. The same trend was detected for seedlings’ survival percentage on 100 mM NaCl (Figure 4B) (Fisher’s exact test with p ≤ 0.05). Similarly, primary root elongation was estimated by screening 10 DAS Arabidopsis SlIPT3 and SlIPT4 complemented plants (Figure 4C). On control medium, the primary root length among the 9AT and 10AT lines significantly differed compared to WT while on the salt-containing medium, no significant changes between the SlIPT3 complemented and WT plants were observed. Arabidopsis plants complemented with SlIPT4 showed significantly longer primary root (3.77 ± 0.41 and 3.85 ± 0.8 cm for 3AT and 5AT, respectively) than WT (3.35 ± 0.58 cm) on control medium, while antagonistic effects were detected on salt-containing medium (Figure 4C, Mann–Whitney U Test with p ≤ 0.05). These results demonstrate that both tomato IPT enzymes are functional in heterologous system. However, in reaction to salt stress the SlIPT4 complemented plants displayed the same characteristics as WT in germination and survival assays, while both of the SlIPT3 complemented lines differed in their response to salinity.Figure 4

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, 165 02, Czech Republic. zizkovae@ueb.cas.cz.

ABSTRACT

Background: 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.

Results: 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.

Conclusions: 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.

No MeSH data available.


Related in: MedlinePlus