Majee, A.; Sairem, B.; Kumar, V.; Sane, A. P.; Sane, V. A.

Summary The function of HSFs, known otherwise as Master thermoregulators,in plant developmental remains largely uninvestigated. In this study, we strategically analyze SlHSFB3a, 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 demonstrates SlHSFB3a overexpressed transgenics display higher lateral root (LR) density and early LR emergence improving root architecture. Generation of CRISPR-Knockout mutants displayed contrasting phenotype, confirming SlHSFB3a vital role in root growth. In SlHSFB3a manipulated roots, concentration gradient auxin responses oscillated with increase in LR number.We highlight the signal transduction of SlHSFB3a mediated auxin activation that enhances tomato LRs. SlHSFB3a directly inhibits auxin repressors, increases auxin flow via ARF7/LOB20 pathway and positively modulates LR growth.