Poster: Tropisms
Abs #
664: Touch response of roots hardness and pore size of growth medium in Arabidopsis thaliana
|
|
Presenter: |
Yamamoto, Chigusa , 37010030@nodai.ac.jp |
Authors | Yamamoto, Chigusa (A) Azami, Kanako (A) Nomiyama, Kyoko (A) Sakata, Yoichi (A) Tanaka, Shigeo (A) | | Affiliations: |
(A): Fac. of Applied Biosci.,Tokyo Univ. of Agric.
|
|
|
As plant roots explore soil, they sense not only gravity stimulus but also a variety of other stimuli ranging from water and nutrient gradients to the hardness and pore size of soil. In the present study, we developed a simple bioassay based on touch response of roots to physical hardness of two-tiered solid growth mediums in Arabidopsis thaliana.
Putting 5,000 T-DNA tagged lines to the bioassay, we have found 3 putative mutants defective in bending reaction to hardness. The isolation of mutants is now in progress to study the molecular mechanism by which roots sense soil hardness.
We have also investigated what genes are expressed in touch response to hard medium in the roots. AFLP-based mRNA fingerprinting (AMF) and northern analysis showed that mRNA coding aspartate aminotransferase1 (ASP1) increased in the stage of touch response. Further studies are now in progress to find out participators in touch response to soil hardness.
Using our bioassay method, the roots of a gravitropic mutant pgm1-1 was found to increase the bending reaction to hardness as compared to the wild type. We also investigated whether or not auxin participated in touch response with aid of an inhibitor of auxin transport, TIBA. The bending reaction was decreased by TIBA. Taken together, these results suggest that gravitropic response may inhibit touch response to soil hardness, and auxin may participate in touch response as well as gravitropism in arabidopsis roots.
@On the other hand, we devised a new bioassay system to investigate whether plant roots distinguished a difference in pore sizes of growth mediums. As a result arabidopsis roots was found to grow differently in response to different pore sizes of the culture mediums.
