SlHSFB3a developmentally regulates lateral root formation by modulating auxin signaling in tomato

Summary The function of HSFs, known otherwise as ‘master thermoregulators,’ in plant developmental remains largely uninvestigated. In this study, we strategically analyzeSlHSFB3a, a class B sub member of HSF transcription factor family, uniquely expresses in age-dependent tomato roots and improves root architecture by synchronizing auxin homeostasis. This data demonstratesSlHSFB3aoverexpressed transgenics display higher lateral root (LR) density and early LR emergence improving root architecture. Generation of CRISPR-Knockout mutants displayed contrasting phenotype, confirmingSlHSFB3a’s vital role in root growth. InSlHSFB3amanipulated roots, concentration gradient auxin responses oscillated with increase in LR number. We highlight the signal transduction ofSlHSFB3amediated auxin activation that enhances tomato LRs.SlHSFB3adirectly inhibits auxin repressors, increases auxin flow via ARF7/LOB20 pathway and positively modulates LR growth.