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Co-silencing of tomato S-adenosylhomocysteine hydrolase genes confers increased immunity against Pseudomonas syringae pv. tomato DC3000 and enhanced tolerance to drought stress.

Li X, Huang L, Hong Y, Zhang Y, Liu S, Li D, Zhang H, Song F - Front Plant Sci (2015)

Bottom Line: Virus-induced gene silencing-based knockdown of individual SlSAHH gene did not affect the growth performance and the response to Pst DC3000.The SlSAHH-co-silenced plants displayed increased resistance to Pst DC3000 but did not alter the resistance to B. cinerea.Co-silencing of SlSAHHs resulted in constitutively activated defense responses including elevated SA level, upregulated expression of defense-related and PAMP-triggered immunity marker genes and increased callose deposition and H2O2 accumulation.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University Hangzhou, China.

ABSTRACT
S-adenosylhomocysteine hydrolase (SAHH), catalyzing the reversible hydrolysis of S-adenosylhomocysteine (SAH) to adenosine and homocysteine, is a key enzyme that maintain the cellular methylation potential in all organisms. We report here the biological functions of tomato SlSAHHs in stress response. The tomato genome contains three SlSAHH genes that encode SlSAHH proteins with high level of sequence identity. qRT-PCR analysis revealed that SlSAHHs responded with distinct expression induction patterns to Pseudomonas syringae pv. tomato (Pst) DC3000 and Botrytis cinerea as well as to defense signaling hormones such as salicylic acid, jasmonic acid and a precursor of ethylene. Virus-induced gene silencing-based knockdown of individual SlSAHH gene did not affect the growth performance and the response to Pst DC3000. However, co-silencing of three SlSAHH genes using a conserved sequence led to significant inhibition of vegetable growth. The SlSAHH-co-silenced plants displayed increased resistance to Pst DC3000 but did not alter the resistance to B. cinerea. Co-silencing of SlSAHHs resulted in constitutively activated defense responses including elevated SA level, upregulated expression of defense-related and PAMP-triggered immunity marker genes and increased callose deposition and H2O2 accumulation. Furthermore, the SlSAHH-co-silenced plants also exhibited enhanced drought stress tolerance although they had relatively small roots. These data demonstrate that, in addition to the functions in growth and development, SAHHs also play important roles in regulating biotic and abiotic stress responses in plants.

No MeSH data available.


Related in: MedlinePlus

Co-silencing of SlSAHHs did not affect the resistance to Botrytis cinerea. Ten-day-old seedlings were infiltrated with agrobacteria carrying TRV-SlSAHHa or TRV-GUS construct and were inoculated by foliar spraying spore suspension (2 × 105 spores/mL) of B. cinerea at 4 weeks after VIGS infiltration. (A) Representative disease symptom on B. cinerea-inoculated TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Photos were taken at 4 days after inoculation. (B)In planta growth of B. cinerea in TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Transcript levels for B. cinerea BcActinA and tomato SlActin genes in B. cinerea-inoculated plants were analyzed using qRT-PCR and in planta fungal growth was shown as ratios of transcript levels of BcActinA/SlActin. Similar results were obtained in independent experiments (A) and data presented in (B) are the means ± SD from three independent experiments. No significant differences at p < 0.05 level was detected in fungal growth between the TRV-SlSAHHa- and TRV-GUS-infiltrated plants.
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Figure 4: Co-silencing of SlSAHHs did not affect the resistance to Botrytis cinerea. Ten-day-old seedlings were infiltrated with agrobacteria carrying TRV-SlSAHHa or TRV-GUS construct and were inoculated by foliar spraying spore suspension (2 × 105 spores/mL) of B. cinerea at 4 weeks after VIGS infiltration. (A) Representative disease symptom on B. cinerea-inoculated TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Photos were taken at 4 days after inoculation. (B)In planta growth of B. cinerea in TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Transcript levels for B. cinerea BcActinA and tomato SlActin genes in B. cinerea-inoculated plants were analyzed using qRT-PCR and in planta fungal growth was shown as ratios of transcript levels of BcActinA/SlActin. Similar results were obtained in independent experiments (A) and data presented in (B) are the means ± SD from three independent experiments. No significant differences at p < 0.05 level was detected in fungal growth between the TRV-SlSAHHa- and TRV-GUS-infiltrated plants.

Mentions: We next examined whether co-silencing of SlSAHHs also affected resistance to B. cinerea, a necrotrophic fungal pathogen that has distinct infection style from that of Pst DC3000. In the B. cinerea-inoculated plants, disease symptom was seen at 2 dpi and the diseased leaves drooped (Figure 4A). However, no significant difference in appearance and symptom of B. cinerea-caused disease was observed between the TRV-SlSAHHa- and TRV-GUS-infiltrated plants (Figure 4A). Further, the in planta fungal growth, represented by ratios of B. cinerea AcActin/tomato SlActin transcripts, in leaves of TRV-SlSAHHa-infiltrated plants was comparable to those in leaves of TRV-GUS-infiltrated plants at 1 and 2 dpi (Figure 4B). These results indicate that co-silencing of SlSAHHs did not affect the resistance against B. cinerea in tomato.


Co-silencing of tomato S-adenosylhomocysteine hydrolase genes confers increased immunity against Pseudomonas syringae pv. tomato DC3000 and enhanced tolerance to drought stress.

Li X, Huang L, Hong Y, Zhang Y, Liu S, Li D, Zhang H, Song F - Front Plant Sci (2015)

Co-silencing of SlSAHHs did not affect the resistance to Botrytis cinerea. Ten-day-old seedlings were infiltrated with agrobacteria carrying TRV-SlSAHHa or TRV-GUS construct and were inoculated by foliar spraying spore suspension (2 × 105 spores/mL) of B. cinerea at 4 weeks after VIGS infiltration. (A) Representative disease symptom on B. cinerea-inoculated TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Photos were taken at 4 days after inoculation. (B)In planta growth of B. cinerea in TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Transcript levels for B. cinerea BcActinA and tomato SlActin genes in B. cinerea-inoculated plants were analyzed using qRT-PCR and in planta fungal growth was shown as ratios of transcript levels of BcActinA/SlActin. Similar results were obtained in independent experiments (A) and data presented in (B) are the means ± SD from three independent experiments. No significant differences at p < 0.05 level was detected in fungal growth between the TRV-SlSAHHa- and TRV-GUS-infiltrated plants.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4561804&req=5

Figure 4: Co-silencing of SlSAHHs did not affect the resistance to Botrytis cinerea. Ten-day-old seedlings were infiltrated with agrobacteria carrying TRV-SlSAHHa or TRV-GUS construct and were inoculated by foliar spraying spore suspension (2 × 105 spores/mL) of B. cinerea at 4 weeks after VIGS infiltration. (A) Representative disease symptom on B. cinerea-inoculated TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Photos were taken at 4 days after inoculation. (B)In planta growth of B. cinerea in TRV-GUS- and TRV-SlSAHHa-infiltrated plants. Transcript levels for B. cinerea BcActinA and tomato SlActin genes in B. cinerea-inoculated plants were analyzed using qRT-PCR and in planta fungal growth was shown as ratios of transcript levels of BcActinA/SlActin. Similar results were obtained in independent experiments (A) and data presented in (B) are the means ± SD from three independent experiments. No significant differences at p < 0.05 level was detected in fungal growth between the TRV-SlSAHHa- and TRV-GUS-infiltrated plants.
Mentions: We next examined whether co-silencing of SlSAHHs also affected resistance to B. cinerea, a necrotrophic fungal pathogen that has distinct infection style from that of Pst DC3000. In the B. cinerea-inoculated plants, disease symptom was seen at 2 dpi and the diseased leaves drooped (Figure 4A). However, no significant difference in appearance and symptom of B. cinerea-caused disease was observed between the TRV-SlSAHHa- and TRV-GUS-infiltrated plants (Figure 4A). Further, the in planta fungal growth, represented by ratios of B. cinerea AcActin/tomato SlActin transcripts, in leaves of TRV-SlSAHHa-infiltrated plants was comparable to those in leaves of TRV-GUS-infiltrated plants at 1 and 2 dpi (Figure 4B). These results indicate that co-silencing of SlSAHHs did not affect the resistance against B. cinerea in tomato.

Bottom Line: Virus-induced gene silencing-based knockdown of individual SlSAHH gene did not affect the growth performance and the response to Pst DC3000.The SlSAHH-co-silenced plants displayed increased resistance to Pst DC3000 but did not alter the resistance to B. cinerea.Co-silencing of SlSAHHs resulted in constitutively activated defense responses including elevated SA level, upregulated expression of defense-related and PAMP-triggered immunity marker genes and increased callose deposition and H2O2 accumulation.

View Article: PubMed Central - PubMed

Affiliation: National Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University Hangzhou, China.

ABSTRACT
S-adenosylhomocysteine hydrolase (SAHH), catalyzing the reversible hydrolysis of S-adenosylhomocysteine (SAH) to adenosine and homocysteine, is a key enzyme that maintain the cellular methylation potential in all organisms. We report here the biological functions of tomato SlSAHHs in stress response. The tomato genome contains three SlSAHH genes that encode SlSAHH proteins with high level of sequence identity. qRT-PCR analysis revealed that SlSAHHs responded with distinct expression induction patterns to Pseudomonas syringae pv. tomato (Pst) DC3000 and Botrytis cinerea as well as to defense signaling hormones such as salicylic acid, jasmonic acid and a precursor of ethylene. Virus-induced gene silencing-based knockdown of individual SlSAHH gene did not affect the growth performance and the response to Pst DC3000. However, co-silencing of three SlSAHH genes using a conserved sequence led to significant inhibition of vegetable growth. The SlSAHH-co-silenced plants displayed increased resistance to Pst DC3000 but did not alter the resistance to B. cinerea. Co-silencing of SlSAHHs resulted in constitutively activated defense responses including elevated SA level, upregulated expression of defense-related and PAMP-triggered immunity marker genes and increased callose deposition and H2O2 accumulation. Furthermore, the SlSAHH-co-silenced plants also exhibited enhanced drought stress tolerance although they had relatively small roots. These data demonstrate that, in addition to the functions in growth and development, SAHHs also play important roles in regulating biotic and abiotic stress responses in plants.

No MeSH data available.


Related in: MedlinePlus