LSD1‐, EDS1‐ and PAD4‐dependent conditional correlation among salicylic acid, hydrogen peroxide, water use efficiency and seed yield in Arabidopsis thaliana

In Arabidopsis thaliana , LESION SIMULATING DISEASE 1 (LSD1), ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) and PHYTOALEXIN DEFICIENT 4 (PAD4) proteins are regulators of cell death (CD) in response to abiotic and biotic stresses. Hormones, such as salicylic acid (SA), and reactive oxygen species, such as hydrogen peroxide (H 2 O 2 ), are key signaling molecules involved in plant CD. The proposed mathematical models presented in this study suggest that LSD1, EDS1 and PAD4 together with SA and H 2 O 2 are involved in the control of plant water use efficiency (WUE), vegetative growth and generative development. The analysis of Arabidopsis wild‐type and single mutants lsd1 , eds1 , and pad4 , as well as double mutants eds1/lsd1 and pad4/lsd1 , demonstrated the strong conditional correlation between SA/H 2 O 2 and WUE that is dependent on LSD1, EDS1 and PAD4 proteins. Moreover, we found a strong correlation between the SA/H 2 O 2 homeostasis of 4‐week‐old Arabidopsis leaves and a total seed yield of 9‐week‐old plants. Altogether, our results prove that SA and H 2 O 2 are conditionally regulated by LSD1/EDS/PAD4 to govern WUE, biomass accumulation and seed yield. Conditional correlation and the proposed models presented in this study can be used as the starting points in the creation of a plant breeding algorithm that would allow to estimate the seed yield at the initial stage of plant growth, based on WUE, SA and H 2 O 2 content.