The journey and new breakthroughs of plant growth regulators in tissue culture

Abstract

Plants use plant growth regulators (PGRs) as chemicals to support their growth, differentiation, and development. Since the early 20th century, plant tissue culture has become an essential tool for plant research, thereby gaining traction on an effective approach to propagate plants in vitro. Beyond all difficulties of the respective time, tissue culture is being used in studies on developmental processes of plants from micropropagation to generation of transgenic plants and many other applications. With natural PGRs, synthetic PGRs are being added to the basket, enabling multiple species to be grown in vitro. Other than widely used auxins and cytokinins, recently characterized PGRs, i.e., brassinosteroids, jasmonic acid, and salicylic acid, are opening new avenues to the ways of plant regeneration, including suspension cultures. Novel methods of characterizing endogenous PGR levels with newly identified PGRs will enable improved protocols for growing recalcitrant species.