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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

QRT-PCR analysis ofSlIPT3andSlIPT4expression. Spatio-temporal expression profile during tomato plant development in vegetative organs (A) and reproductive organs (B). Regulation of SlIPT3 and SlIPT4 expression by CK treatment: Effects of tZ (10 μM) treatment on SlIPT3 and SlIPT4 expression (C) and the expression levels of CK response regulators SlARR1, SlARR4 and SlARR12(D). Actin and GAPDH were used as internal controls for normalization of SlIPT3 and SlIPT4 transcript levels. Data represent means and SD of three replicates. *statistically significant difference from time 0 h (unpaired two-tailed Student’s t-test, p ≤ 0.05). **statistically significant difference from time 0 h after Šidák correction for testing of multiple points (multiple unpaired two-tailed Student’s t-test, overall α = 0.05, individual p ≤ 0.0127). YL, young leaves; OL, old leaves; Ro, roots; St, stem; Bud, bud; Flo, flower; Gre, green stage; Bre, breaker stage; Red, red stage of tomato development.
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Fig6: QRT-PCR analysis ofSlIPT3andSlIPT4expression. Spatio-temporal expression profile during tomato plant development in vegetative organs (A) and reproductive organs (B). Regulation of SlIPT3 and SlIPT4 expression by CK treatment: Effects of tZ (10 μM) treatment on SlIPT3 and SlIPT4 expression (C) and the expression levels of CK response regulators SlARR1, SlARR4 and SlARR12(D). Actin and GAPDH were used as internal controls for normalization of SlIPT3 and SlIPT4 transcript levels. Data represent means and SD of three replicates. *statistically significant difference from time 0 h (unpaired two-tailed Student’s t-test, p ≤ 0.05). **statistically significant difference from time 0 h after Šidák correction for testing of multiple points (multiple unpaired two-tailed Student’s t-test, overall α = 0.05, individual p ≤ 0.0127). YL, young leaves; OL, old leaves; Ro, roots; St, stem; Bud, bud; Flo, flower; Gre, green stage; Bre, breaker stage; Red, red stage of tomato development.

Mentions: The expression patterns of SlIPT3 and SlIPT4 in various tomato vegetative and reproductive organs from plants cultivated in the greenhouse under normal growth conditions, including three stages of fruit development and ripening, were investigated by qRT-PCR (Figure 6A and B). In general, SlIPT3 transcripts were much more abundant than SlIPT4 ones in all the tested organs. Both genes were expressed in young and old leaves, roots and stems of tomato plants. In vegetative tissues, SlIPT3 transcripts were weakly detected in young leaves but highly accumulated in stems, roots and old leaves. In contrast, SlIPT4 was preferentially expressed in young leaves (Figure 6A). In reproductive tissues, SlIPT3 transcripts were abundant in buds and flowers, then rapidly decreased during tomato fruit maturation with higher levels of transcripts in the breaker stage. SlIPT4 was preferentially expressed in buds, then continuously declined until the breaker stage and reached its peak expression at the red stage of tomato fruit (Figure 6B). Taken together, these data indicate that SlIPT3 and SlIPT4 display distinct expression profiles during tomato development.Figure 6


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)

QRT-PCR analysis ofSlIPT3andSlIPT4expression. Spatio-temporal expression profile during tomato plant development in vegetative organs (A) and reproductive organs (B). Regulation of SlIPT3 and SlIPT4 expression by CK treatment: Effects of tZ (10 μM) treatment on SlIPT3 and SlIPT4 expression (C) and the expression levels of CK response regulators SlARR1, SlARR4 and SlARR12(D). Actin and GAPDH were used as internal controls for normalization of SlIPT3 and SlIPT4 transcript levels. Data represent means and SD of three replicates. *statistically significant difference from time 0 h (unpaired two-tailed Student’s t-test, p ≤ 0.05). **statistically significant difference from time 0 h after Šidák correction for testing of multiple points (multiple unpaired two-tailed Student’s t-test, overall α = 0.05, individual p ≤ 0.0127). YL, young leaves; OL, old leaves; Ro, roots; St, stem; Bud, bud; Flo, flower; Gre, green stage; Bre, breaker stage; Red, red stage of tomato development.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig6: QRT-PCR analysis ofSlIPT3andSlIPT4expression. Spatio-temporal expression profile during tomato plant development in vegetative organs (A) and reproductive organs (B). Regulation of SlIPT3 and SlIPT4 expression by CK treatment: Effects of tZ (10 μM) treatment on SlIPT3 and SlIPT4 expression (C) and the expression levels of CK response regulators SlARR1, SlARR4 and SlARR12(D). Actin and GAPDH were used as internal controls for normalization of SlIPT3 and SlIPT4 transcript levels. Data represent means and SD of three replicates. *statistically significant difference from time 0 h (unpaired two-tailed Student’s t-test, p ≤ 0.05). **statistically significant difference from time 0 h after Šidák correction for testing of multiple points (multiple unpaired two-tailed Student’s t-test, overall α = 0.05, individual p ≤ 0.0127). YL, young leaves; OL, old leaves; Ro, roots; St, stem; Bud, bud; Flo, flower; Gre, green stage; Bre, breaker stage; Red, red stage of tomato development.
Mentions: The expression patterns of SlIPT3 and SlIPT4 in various tomato vegetative and reproductive organs from plants cultivated in the greenhouse under normal growth conditions, including three stages of fruit development and ripening, were investigated by qRT-PCR (Figure 6A and B). In general, SlIPT3 transcripts were much more abundant than SlIPT4 ones in all the tested organs. Both genes were expressed in young and old leaves, roots and stems of tomato plants. In vegetative tissues, SlIPT3 transcripts were weakly detected in young leaves but highly accumulated in stems, roots and old leaves. In contrast, SlIPT4 was preferentially expressed in young leaves (Figure 6A). In reproductive tissues, SlIPT3 transcripts were abundant in buds and flowers, then rapidly decreased during tomato fruit maturation with higher levels of transcripts in the breaker stage. SlIPT4 was preferentially expressed in buds, then continuously declined until the breaker stage and reached its peak expression at the red stage of tomato fruit (Figure 6B). Taken together, these data indicate that SlIPT3 and SlIPT4 display distinct expression profiles during tomato development.Figure 6

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