N‐glycan containing a core α1,3‐fucose residue is required for basipetal auxin transport and gravitropic response in rice (Oryza sativa)

Abstract

SummaryIn plants, a1,3-fucosyltransferase (FucT) catalyzes the transfer of fucose from GDP-fucose to asparagine-linked GlcNAc of the N-glycan core in the medial Golgi. To explore the physiological significance of this processing, we isolated two Oryza sativa (rice) mutants (fuct-1 and fuct-2) with loss of FucT function.Biochemical analyses of the N-glycan structure confirmed that a1,3-fucose is missing from the N-glycans of allelic fuct-1 and fuct-2. Compared with the wild-type cv Kitaake, fuct-1 displayed a larger tiller angle, shorter internode and panicle lengths, and decreased grain filling as well as an increase in chalky grains with abnormal shape. The mutant allele fuct-2 gave rise to similar developmental abnormalities, although they were milder than those of fuct-1.Restoration of a normal tiller angle in fuct-1 by complementation demonstrated that the phenotype is caused by the loss of FucT function. Both fuct-1 and fuct-2 plants exhibited reduced gravitropic responses. Expression of the genes involved in tiller and leaf angle control was also affected in the mutants.We demonstrate that reduced basipetal auxin transport and low auxin accumulation at the base of the shoot in fuct-1 account for both the reduced gravitropic response and the increased tiller angle.

A Core Regulatory Pathway Controlling Rice Tiller Angle Mediated by the LAZY1-Dependent Asymmetric Distribution of Auxin

“…Rice tiller angle is an important agronomic trait that contributes to plant architecture and grain yield by determining the compactness of the plants. Several genes that determine rice tiller angle have been cloned and characterized (Li et al, 2007;Yoshihara and Iino, 2007;Yu et al, 2007;Jin et al, 2008;Tan et al, 2008;Okamura et al, 2013;Wu et al, 2013;Lu et al, 2015a;Dong et al, 2016;Harmoko et al, 2016); however, the regulatory network or pathway of these genes involved in the control of rice tiller angle is largely unknown. Moreover, progress in identifying new genes has been limited, which limits applications in improving rice architecture and elucidation of the molecular mechanisms controlling tiller angle.…”

“…LPA1, encoding the plant-specific INDETERMINATE DOMAIN (IDD) protein, an ortholog of Arabidopsis IDD15/SHOOT GRAVITROPISM5 (SGR5), regulates shoot gravitropism and tiller angle by affecting the rate of amyloplast sedimentation (Wu et al, 2013). Reverse genetics studies have also shown that ADP-GLUCOSE PYRO-PHOSPHORYLASE1 (AGPL1), PIN-FORMED2 (PIN2), Oryza sativa LEAF AND TILLER ANGLE INCREASED CONTROLLER (OsLIC), and α-1,3-FUCOSYLTRANSFERASE (FUCT) are regulators of rice tiller angle Chen et al, 2012;Okamura et al, 2013;Harmoko et al, 2016). However, the molecular mechanism underlying the control of tiller angle and the functional relationships among known regulatory genes remain to be elucidated.…”

“…Previous studies have indicated that rice tiller angle is strongly related to plant gravitropic responses (Abe and Suge, 1993;Li et al, 2007;Wu et al, 2013;Okamura et al, 2015;Roychoudhry and Kepinski, 2015;Harmoko et al, 2016). In plants, gravitropism involves the perception of gravity and signal transduction cascades that lead to an asymmetric distribution of auxin and differential growth between the upper and lower sides of responding organs (Strohm et al, 2012).…”

Integrative RNA- and miRNA-Profile Analysis Reveals a Likely Role of BR and Auxin Signaling in Branch Angle Regulation of B. napus

“…Asymmetric distribution of auxin has long been regarded as the main factor that affects shoot gravitropism [15,16], a key component in controlling branch orientation. Changes in the expression levels of genes involved in auxin synthesis or signaling transduction have been shown to result in differences in the tiller angle and gravitropic response [8].…”

Impact of Post-Translational Modifications of Crop Proteins under Abiotic Stress

“…The α1,3-fucosyltransferase catalyzes the transfer of fucose to the N -glycan cores. Loss of function of fucosyltransferase resulted in reduced gravitropic responses in rice [67]. The above-mentioned results indicate that tolerance against environmental stresses in rice depends on how accurately proteins are transported and localized using N -glycans as delivery tags.…”