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A mechanistic framework for auxin dependent Arabidopsis root hair elongation to low external phosphate

Authors:

Rahul Bhosale, Jitender Giri, Bipin K. Pandey, Ricardo F.H. Giehl, Anja Hartmann,
Richard Traini
, Jekaterina Truskina, Nicola Leftley, Meredith Hanlon, Kamal Swarup, Afaf Rashed, Ute Voß, Jose Alonso, Anna Stepanova, Jeonga Yun, Karin Ljung, Kathleen M. Brown, Jonathan P. Lynch, Liam Dolan, Teva Vernoux, Anthony Bishopp, Darren Wells, Nicolaus von Wirén, Malcolm J. Bennett & Ranjan Swarup

 

Source:

Nature Communications 2018(9):1409

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Abstract:

Phosphate (P) is an essential macronutrient for plant growth. Roots employ adaptive mechanisms to forage for P in soil. Root hair elongation is particularly important since P is immobile. Here we report that auxin plays a critical role promoting root hair growth in Arabidopsis in response to low external P. Mutants disrupting auxin synthesis (taa1) and transport (aux1) attenuate the low P root hair response. Conversely, targeting AUX1 expression in lateral root cap and epidermal cells rescues this low P response in aux1. Hence auxin transport from the root apex to differentiation zone promotes auxin-dependent hair response to low P. Low external P results in induction of root hair expressed auxin-inducible transcription factors ARF19, RSL2, and RSL4. Mutants lacking these genes disrupt the low P root hair response. We conclude auxin synthesis, transport and response pathway components play critical roles regulating this low P root adaptive response.