ORCID Profile
0000-0003-2451-4148
Current Organisation
Foshan University
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Publisher: Oxford University Press (OUP)
Date: 21-05-2018
DOI: 10.1104/PP.18.00188
Publisher: Informa UK Limited
Date: 02-09-2018
Publisher: Wiley
Date: 11-03-2021
DOI: 10.1111/NPH.17176
Abstract: P‐type H + ATPases mediate active H + efflux from plant cells. They generate a proton motive force across the plasma membrane, providing the free energy to drive the transport of other solutes, partly by coupling to H + influx. Wegner & Shabala (2020) recently suggested that passive H + influx can exceed pump‐driven efflux due to ‘active buffering’, that is, cytosolic H + scavenging and apoplastic H + generation by metabolism (‘biochemical pH cl ’). Charge balance is provided by K + efflux or anion influx. Here, this hypothesis is extended to net H + efflux: even though H + pumping is faster than backflow via symporters and antiporters, a progressive increase in the transmembrane pH gradient is avoided. Cytosolic H + release is associated with bicarbonate formation from CO 2 . Bicarbonate serves as substrate for the PEPCase, catalyzing the reaction from phosphoenolpyruvate to oxaloacetate, which is subsequently reduced to malate. Organic anions such as malate and citrate are released across the plasma membrane and are (partly) protonated in the apoplast, thus limiting pump‐induced acidification. Moreover, a ‘biophysical pH cl ’ is introduced, that is, adjustment of apoplastic/cytosolic pH involving net H + fluxes across the plasma membrane, while the gradient between compartments is maintained. The cl s are not mutually exclusive but are likely to coexist.
Publisher: Wiley
Date: 23-02-2023
DOI: 10.1111/TPJ.16129
Abstract: The supply of boron (B) alleviates the toxic effects of aluminum (Al) on root growth however, the mechanistic basis of this process remains elusive. This study filled this knowledge gap, demonstrating that boron modifies auxin distribution and transport in Al‐exposed Arabidopsis roots. In B‐deprived roots, treatment with Al induced an increase in auxin content in the root apical meristem zone (MZ) and transition zone (TZ), whereas in the elongation zone (EZ) the auxin content was decreased beyond the level required for adequate growth. These distribution patterns are explained by the fact that basipetal auxin transport from the TZ to the EZ was disrupted by Al‐inhibited PIN‐FORMED 2 (PIN2) endocytosis. Experiments involving the modulation of protein biosynthesis by cycloheximide (CHX) and transcriptional regulation by cordycepin (COR) demonstrated that the Al‐induced increase of PIN2 membrane proteins was dependent upon the inhibition of PIN2 endocytosis, rather than on the transcriptional regulation of the PIN2 gene. Experiments reporting on the profiling of Al 3+ and PIN2 proteins revealed that the inhibition of endocytosis of PIN2 proteins was the result of Al‐induced limitation of the fluidity of the plasma membrane. The supply of B mediated the turnover of PIN2 endosomes conjugated with indole‐3‐acetic acid (IAA), and thus restored the Al‐induced inhibition of IAA transport through the TZ to the EZ. Overall, the reported results demonstrate that boron supply mediates PIN2 endosome‐based auxin transport to alleviate Al toxicity in plant roots.
Publisher: Wiley
Date: 09-06-2023
DOI: 10.1111/TPJ.16324
Abstract: The mechanistic basis by which boron (B) deprivation inhibits root growth via the mediation of root apical auxin transport and distribution remains elusive. This study showed that B deprivation repressed root growth of wild‐type Arabidopsis seedlings, which was related to higher auxin accumulation (observed with DII‐VENUS and DR5‐GFP lines) in B‐deprived roots. Boron deprivation elevated the auxin content in the root apex, coinciding with upregulation of the expression levels of auxin biosynthesis‐related genes ( TAA1 , YUC3 , YUC9 , and NIT1 ) in shoots, but not in root apices. Phenotyping experiments using auxin transport‐related mutants revealed that the PIN2/3/4 carriers are involved in root growth inhibition caused by B deprivation. B deprivation not only upregulated the transcriptional levels of PIN2 /3/4, but also restrained the endocytosis of PIN2/3/4 carriers (observed with PIN‐Dendra2 lines), resulting in elevated protein levels of PIN2/3/4 in the plasma membrane. Overall, these results suggest that B deprivation not only enhances auxin biosynthesis in shoots by elevating the expression levels of auxin biosynthesis‐related genes but also promotes the polar auxin transport from shoots to roots by upregulating the gene expression levels of PIN2/3/4 , as well as restraining the endocytosis of PIN2/3/4 carriers, ultimately resulting in auxin accumulation in root apices and root growth inhibition.
No related grants have been discovered for Xuewen Li.