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

Kang Xu 1, Haoran Zeng 1, Feiyang Lin 1, Emi Yumoto 2, Masashi Asahina 2 3, Ken-Ichiro Hayashi 4, Hidehiro Fukaki 5, Hisashi Ito 6, Masaaki K Watahiki 1 7

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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Aug 9:kiae405

doi: 10.1093/plphys/kiae405.