Exogenous application of the apocarotenoid retinaldehyde negatively regulates auxin-mediated root growth

Xu K, Zeng H, Lin F, Yumoto E, Asahina M, Hayashi KI, Fukaki H, Ito H, Watahiki MK.

Root development is essential for plant survival. The lack of carotenoid biosynthesis in the phytoene desaturase 3 (pds3) mutant results in short primary roots (PR) and reduced lateral root (LR) formation. In this study, we showed that short-term inhibition of PDS by fluridone suppresses PR growth in WT, but to a lesser extent in auxin mutants of Arabidopsis (Arabidopsis thaliana). Such an inhibition of PDS activity increased endogenous indole-3-acetic acid (IAA) levels, promoted auxin signaling, and partially complemented the PR growth of an auxin deficient mutant, the YUCCA 3 5 7 8 9 quadruple mutant (yucQ). The exogenous application of retinaldehyde (retinal), an apocarotenoid derived from β-carotene, complemented the fluridone-induced suppression of root growth, as well as the short roots of the pds3 mutant. Retinal also partially complemented the auxin-induced suppression of root growth. These results suggest that retinal may play a role in regulating root growth by modulating endogenous auxin levels.

Plant Physiol
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196

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1659

1673

doi: 10.1093/plphys/kiae405.