4. Phytohormones orchestrate cereals’ root system architecture
Environmental factors and phytohormone shape cereals’ RSA. However, the
hormonal interplay regulating RSA is very complex. Figure 1B offers a
simplified overview. For further information, one can refer to recent
reviews on the topic.
Auxin is the central regulator of the RSA. This is supported by the fact
that most of the mutants reported being affected in their RSA are
related to auxin synthesis, transport or signalling pathway. In rice, a
recent reviewalso highlights auxin’s central role in root elongation and
lateral and crown roots initiation and emergence. However, other
hormones such as cytokinins (CKs), ethylene, abscisic acid (ABA),
gibberellins, brassinosteroids and strigolactones should not stay aside.