A role for the auxin precursor anthranilic acid in root gravitropism via regulation of PIN‐FORMED protein polarity and relocalisation in Arabidopsis

Abstract

Summary distribution of auxin within plant tissues is of great importance for developmental plasticity, including root gravitropic growth. Auxin flow is directed by the subcellular polar distribution and dynamic relocalisation of auxin transporters such as the PIN‐FORMED (PIN) efflux carriers, which can be influenced by the main natural plant auxin indole‐3‐acetic acid (IAA). Anthranilic acid (AA) is an important early precursor of IAA and previously published studies with AA analogues have suggested that AA may also regulate PIN localisation. Using Arabidopsis thaliana as a model species, we studied an AA‐deficient mutant displaying agravitropic root growth, treated seedlings with AA and AA analogues and transformed lines to over‐produce AA while inhibiting its conversion to downstream IAA precursors. We showed that AA rescues root gravitropic growth in the AA‐deficient mutant at concentrations that do not rescue IAA levels. Overproduction of AA affects root gravitropism without affecting IAA levels. Treatments with, or deficiency in, AA result in defects in PIN polarity and gravistimulus‐induced PIN relocalisation in root cells. Our results revealed a previously unknown role for AA in the regulation of PIN subcellular localisation and dynamics involved in root gravitropism, which is independent of its better known role in IAA biosynthesis.

An R2R3-MYB Transcription Factor PgFLP Directly Activates PgPIN10 to Regulate the GSA of Adventitious Root in Pomegranate

“…1a). The PINs have been found to conducive to nearly every step of auxin uxes [3,18,35,20] and the auxin distribution patterns have been predicted and explained through auxin transport [2,6,1]. In this study, the expression of PgPIN1 and PgPIN10 showed higher in LBS than TSH (Fig.…”

“…The PINs have been found to conducive to nearly every step of auxin uxes [3,18,35,20] and the auxin distribution patterns have been predicted and explained through auxin transport [2,6,1]. FLP and MYB88 have been found to can regulate root gravitropism [27], the late stages of stomatal development [11], cold hardiness [30], female reproductive development [17], and guard mother cell proliferation [11,31].…”

“…In addition, the polar auxin transport is bene cial to the root bending under obstacle avoidance [13]. The auxin distribution patterns have been predicted and explained through auxin transport [2,6,1]. The AtPIN3 shows remarkably dynamic expression during the root gravitropism and patterning of stomatal complexes in Arabidopsis [14,27].…”

Magnaporthe oryzae Systemic Defense Trigger 1 (MoSDT1)-Mediated Metabolites Regulate Defense Response in Rice

“…Benzenoids accumulated at different time-points in M. oryzae-infected transgenic rice, in which salicylic acid and anthranilic acid (Vitamin L1) accumulated at three-time points. Anthranilic acid (AA) is a vital precursor in the synthesis of major auxin, indole-3-acetic acid (IAA) [24], essential for maintaining the growth of infected transgenic rice. While salicylic acid plays a vital role in defense response [25], suggesting that MoSDT1 may play a role in balancing rice growth and defenses.…”

“…Firstly, rice leaves were inoculated with spores of M. oryzae strain 95234I-1b, and then sprayed with exogenous compounds after 72 h at three concentrations (Supplementary Table 2), and the concentrations of six compounds were prepared [21,24,26]. Disease index =∑ (number of leaves at each grade × representative values at all grades)/(review total leaf number × highest grade representative value)×100 [18].…”