Poster: Salinity

Abs # 166: Supressor mutations of sos3 NaCl hypersensitivity

Presenter:	Hasegawa, Paul M, paul.m.hasegawa.1@purdue.edu
Authors	Hasegawa, Paul M (A)   Miura, Kenji  (A)   Rus, Ana  (A)   Sharkhuu, Altanbadralt  (A)   Lee, Byeong-ha  (B)   Yokoi, Shuji  (A)   Zhu, Jian-Kang  (B)   Bressan, Ray A (A)
Affiliations:	(A): Center for Plant Environmental Stress Physiology, Purdue University (B): Department of Plant Sciences, University of Arizona

T₂ seedlings of a T-DNA insertion line population (~100,000 lines) that was generated in the Arabidopsis thaliana Col-0 gl1 sos3-1 genetic background were screened for genetic suppressor and enhancer mutations. Sixteen independent mutations were identified that suppressed sos3-1 NaCl hypersensitivity. Mutant characterization revealed that seven of these are hkt1 alleles (hkt1-1 and 2, hkt1-4 through 8) and all of these also suppress the K⁺ deficiency of sos3-1. Gain-of-function analysis confirmed that AtHKT1 is a Na⁺ uptake system that negatively regulates K⁺ acquisition. Another suppressor mutation (mzf1-1) of sos3-1 exhibits a Pi-deficient phenotype. The T-DNA insertion of mzf1-1 is located in a gene that encodes a putative transcription factor with a Miz-type zinc finger (MZF1) domain. mzf1-2 and mzf1-3 were identified in the SIGnAL database and obtained from Arabidopsis Biological Resource Center. The mzf1-2 and mzf1-3 seedlings exhibit the same Pi-deficient phenotype as the sos3-1 mzf1-1 seedlings.