AUTHOR=Huang Jia-Bao , Zou Yi , Zhang Xiaojing , Wang Mingyan , Dong Qingkun , Tao Li-Zhen 

TITLE=RIBOSE PHOSPHATE ISOMERSASE 1 Influences Root Development by Acting on Cell Wall Biosynthesis, Actin Organization, and Auxin Transport in Arabidopsis

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01641

DOI=10.3389/fpls.2019.01641

ISSN=1664-462X

ABSTRACT=<p>Cell wall biosynthesis plays essential roles in cell division and expansion and thus is fundamental to plant growth and development. In this work, we show that an <italic>Arabidopsis</italic> mutant <italic>dpr3</italic>, isolated by a forward genetic screen, displays embryo defects and short, swelling primary root with the failure of maintenance of root apical meristem reminiscent to several cell wall–deficient mutants. Map-based cloning identified <italic>dpr3</italic> is a mutant allele of <italic>RIBOSE PHOSPHATE ISOMERSASE 1</italic> (<italic>RPI1</italic>), an enzyme involved in cellulose synthesis. Cellulose content in the mutant was dramatically decreased. Moreover, <italic>dpr3</italic> (<italic>rpi1</italic> from hereon) caused aberrant auxin distribution, as well as defective accumulation of root master regulators PLETHORA (PLT1 and PLT2) and misexpression of auxin response factor 5 (<italic>MONOPTEROS, MP</italic>). The abnormal auxin distribution is likely due to the reduced accumulation of auxin efflux transporters PIN-FORMED (PIN1 and PIN3). Surprisingly, we found that the orientation of actin microfilaments was severely altered in <italic>rpi1</italic> root cells, whereas the cortical microtubules stay normal. Our study provides evidence that the defects in cellulose synthesis <italic>in rpi1</italic> affect polar auxin transport possibly connected with altered F-actin organization, which is critically important for vesicle trafficking, thus exerting effects on auxin distribution, signaling, and auxin-mediated plant development.</p>