토마토에서 칼슘수송체와 칼슘결합단백질 공동발현에 의한 칼슘결핍유사증상의 완화

Restriction of Ca2+ deficiency-Like symptoms by co-expressing a Ca2+ transporter and a Ca2+-binding protein in tomato

Here we focused on tip-burn and blossom-end rot (BER) symptoms in the tomato plants expressing the constitutively active form of Ca2+/H+ antiporter (sCAX1) and/or a Ca-binding protein (calreticulin, CRT) genes during their whole growth period. Conclusively we demonstrated that CRT is able to suppress the tip-burn and BER symptoms that were induced by sCAX1. Under poor nutrition condition, tomato plants overexpressing sCAX1 showed severe necrotic collapses in both roots and shoot polar tissues, which are in accordance with Ca2+ deficient symptoms frequently observed in an agricultural cultivation of tomato. Reciprocal grafting trials using sCAX1 and wild type plants revealed that the tip-burn symptom by sCAX1 overexpression is not caused by hindrance of Ca2+ uptake from soil. We constructed CRT overexpressing transgenic tomatoes, and crossed them with sCAX1 transgenic plants to investigate the effects of CRT on the symptoms of sCAX1 transgenic plants. Coexpression of sCAX1 and CRT significantly suppressed the Ca2+ deficient symptoms of sCAX1 transgenic plants. Those results suggest the model that Ca2+ homeostasis disturbed by the overexpression of sCAX1 may be suppressed by the co-expression of CRT.