| Outline of Annual Research Achievements |
1. We have examined the growth phenotypes of the Arabidopsis <max2ahk2,3> triple mutant. The root- and shoot-related traits of the <max2ahk2,3> mutant plants and wild-type (WT) were compared to examine how the interactions and crosstalk between the cytokinin (CK) and max2 signaling pathways affect plant growth and development. Bolting, flowering and silique ripening times of the genotypes were determined and compared. Furthermore, we studied the drought stress tolerance of the <max2ahk2,3> triple mutant.
2. Because the strigolactone (SL) and karrikin (KAR) signaling pathways shares the ‘checkpoint’ MAX2, we have studied the function of the KAR-receptor KAI2 mutant in drought response. We found that KAI2 acts as a positive regulator of plant adaptation to drought. Results were published in PLoS Genetics (1).
3. Following the important finding on the KAI2, we have also made the <d14ahk2,3> and <kai2ahk2,3> mutants for studying the specific crosstalk between the SL and cytokinin (CK), as well as between the KAR and CK pathways.
Publication:
(1) Li W, Nguyen KH, Chu HD, Ha CV, Watanabe Y, Osakabe Y, Leyva-Gonzalez MA, Sato M, Toyooka K, Voges L, Tanaka M, Mostofa MG, Seki M, Seo M, Yamaguchi S, Nelson DC, Herrera-Estrella L, Tran LS (2017). The karrikin receptor KAI2 promotes drought resistance in Arabidopsis thaliana. PLoS Genet 13:e1007076.
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| Strategy for Future Research Activity |
Aim 1: We will study the function CK and max2 signalings in callus development by analyzing the <max2ahk2,3> , <ahk2,3> and <max2> mutants.
Aim 2: We will study the function of the SL-specific receptor D14 in plant adaptation to drought following the procedure described in (1).
Aim 3: We will characterize the morphological phenotype of <d14ahk2,3> and <kai2ahk2,3> mutants under normal conditions. The root- and shoot-related traits of the already constructed <d14ahk2,3> and <kai2ahk2,3> mutants and WT will be compared as described previously (2) to examine how interactions and crosstalk between CK and SL, and CK and KAR signaling pathways affect plant growth and development. Bolting, flowering and silique ripening times of the genotypes will also be determined and compared according to (3).
Aim 4: We will characterize the stress-tolerant phenotype of d14ahk2,3 and kai2ahk2,3 mutants under drought, and potentially under salinity as previously described in (1, 3).
(1) Li W, Nguyen KH, Chu HD, Ha CV, Watanabe Y, Osakabe Y, Leyva-Gonzalez MA, Sato M, Toyooka K, Voges L, Tanaka M, Mostofa MG, Seki M, Seo M, Yamaguchi S, Nelson DC, Herrera-Estrella L, Tran LS (2017). PLoS Genet 13:e1007076. (2) Li W, Nguyen KH, Watanabe Y, Yamaguchi S, Tran LS (2016) Biochem Biophys Res Commun 16:478:521-6. (3) Nishiyama R, Watanabe Y, Fujita Y, Le DT, Kojima M, Werner T, Vankova R, Yamaguchi-Shinozaki K, Shinozaki K, Kakimoto T, Sakakibara H, Schmulling T, Tran LS (2011) Plant Cell 23:2169-83.
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