Effect of Hypomagnetic Field on Hypocotyl Growth in Arabidopsis

Abstract

Cryptochrome was thought of as a magnetoreceptor based on the proposal that photochemical reactions worked as the sensor of geomagnetic field (GMF). To test the effect of GMF on cryptochrome, we created a hypomagnetic field environment by eliminating the local GMF using Helmholtz coils and grew wild-type Arabidopsis and cryptochrome double mutant, cry1/cry2, in the hypomagnetic field under blue light. We found that hypocotyl length of wild-type Arabidopsis rather than cry1/cry2 mutants was longer in hypomagnetic field than in local GMF. Moreover, we detected gibberellin (GA) levels in Arabidopsis in hypomagnetic field and found that GA4 and GA9 were increased in wild-type seedlings instead of cry1/cry2 mutants. Furthermore, transcription of GA20-oxidase genes (GA20ox1, GA20ox2, and GA20ox3) and GA3-oxidase genes (GA3ox1, GA3ox2, GA3ox3, and GA3ox4) was enhanced. Our results indicate that hypomagnetic field suppresses blue light-dependent inhibition of hypocotyl growth in Arabidopsis, and that cryptochrome and GAs are involved in the effect of hypomagnetic field on hypocotyl growth.