Figure 8.

HAK5 Expression Is Altered in Ethylene Mutants Grown under Complete Nutrient Conditions and K⁺-Deficient Conditions.

(A) HAK5 expression levels in ein2-1 and ctr1-1 mutants under K⁺-sufficient (+K, 5 mM K⁺) and K⁺-deficient (no K⁺) conditions relative to those in the wild type grown on complete medium (set to 1).

(B) and (C) Relative HAK5 expression levels in the combinatorial loss-of-function mutants of five ethylene receptors under K⁺-sufficient (+K, 5 mM K⁺) conditions.

Three-day-old seedlings were deprived of K⁺ for 24 h. The expression data were obtained by quantitative RT-PCR. A β-tubulin gene was used as a reference gene. The fold change of HAK5 level in each sample was compared with the HAK5 level of the wild-type control under K⁺-sufficient conditions. Different letters above the bars indicate values that are significantly different (n = 3, P < 0.05; t test). Col-0 was used as a control for the ein2-1, ctr1-1, etr1-6, etr2-3, ein4-4, and etr1-6 etr2-3 ein4-4 plants, whereas Wassilewskija (WS) was used as a control for the ers1-3, ers2-3, and ers1-2 ers2-3 plants. The triple mutant etr2-3 ers2-3 ein4-4 is in the background of Col-0 and Wassilewskija. All loss-of-function mutants are predicted to be null mutants, except for ers1-2, which is known to have a decreased level of full-length transcripts (Binder, 2008).