Soybean BRU1 Encodes a Functional Xyloglucan Endotransglycosylase That is Highly Expressed in Inner Epicotyl Tissues during Brassinosteroid-Promoted Elongation

Oh, Man‐Ho; Romanow, William G.; Smith, Rachel Charlotte; Zamski, E.; Sasse, Jenneth M.; Clouse, Steven D.

doi:10.1093/oxfordjournals.pcp.a029283

Cited by 76 publications

(38 citation statements)

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“…In elongating soybean epicotyls, BR application results in increased plastic extensibility of the walls within 2 h, with a concomitant increase in BRU1 mRNA levels (Zurek and Clouse, 1994). The BRU1 gene is regulated specifically by BRs during the early stages of elongation, and enzyme assays with recombinant protein show that BRU1 is indeed a functional XET (Oh et al, 1998). Moreover, the mechanism of BR regulation of BRU1 has been shown to be posttranscriptional.…”

Section: Discussionmentioning

confidence: 99%

A Putative Role for the Tomato Genes DUMPY and CURL-3 in Brassinosteroid Biosynthesis and Response

et al. 2000

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The dumpy (dpy) mutant of tomato (Lycopersicon esculentum Mill.) exhibits short stature, reduced axillary branching, and altered leaf morphology. Application of brassinolide and castasterone rescued the dpy phenotype, as did C-23-hydroxylated, 6-deoxo intermediates of brassinolide biosynthesis. The brassinolide precursors campesterol, campestanol, and 6-deoxocathasterone failed to rescue, suggesting that dpy may be affected in the conversion of 6-deoxocathasterone to 6-deoxoteasterone, similar to the Arabidopsis constitutive photomorphogenesis and dwarfism (cpd) mutant. Measurements of endogenous brassinosteroid levels by gas chromatography-mass spectrometry were consistent with this hypothesis. To examine brassinosteroid-regulated gene expression in dpy, we performed cDNA subtractive hybridization and isolated a novel xyloglucan endotransglycosylase that is regulated by brassinosteroid treatment. The curl-3 (cu-3) mutant (Lycopersicon pimpinellifolium [Jusl.] Mill.) shows extreme dwarfism, altered leaf morphology, de-etiolation, and reduced fertility, all strikingly similar to the Arabidopsis mutant brassinosteroid insensitive 1 (bri1). Primary root elongation of wild-type L. pimpinellifolium seedlings was strongly inhibited by brassinosteroid application, while cu-3 mutant roots were able to elongate at the same brassinosteroid concentration. Moreover, cu-3 mutants retained sensitivity to indole-3-acetic acid, cytokinins, gibberellin, and abscisic acid while showing hypersensitivity to 2,4-dichlorophenoxyacetic acid in the root elongation assay. The cu-3 root response to hormones, coupled with its bri1-like phenotype, suggests that cu-3 may also be brassinosteroid insensitive.

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Section: Discussionmentioning

confidence: 99%

A Putative Role for the Tomato Genes DUMPY and CURL-3 in Brassinosteroid Biosynthesis and Response

et al. 2000

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“…In these cases, XET is thought to play a role in wall degradation or in poorly defined XG rearrangements. Several studies have reported XET expression in unspecified cell types of primary vascular tissues (Xu et al, 1995;Antosiewicz et al, 1997;Oh et al, 1998;Vissenberg et al, 2000;Herbers et al, 2001) and the internal phloem of tobacco stems (Medford et al, 1991). These findings suggest that XET may be involved in the formation of secondary walls of xylem and/or phloem cells.…”

Section: Introductionmentioning

confidence: 91%

Xyloglucan Endotransglycosylases Have a Function during the Formation of Secondary Cell Walls of Vascular Tissues

et al. 2002

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Xyloglucan transglycosylases (XETs) have been implicated in many aspects of cell wall biosynthesis, but their function in vascular tissues, in general, and in the formation of secondary walls, in particular, is less well understood. Using an in situ XET activity assay in poplar stems, we have demonstrated XET activity in xylem and phloem fibers at the stage of secondary wall formation. Immunolocalization of fucosylated xylogucan with CCRC-M1 antibodies showed that levels of this species increased at the border between the primary and secondary wall layers at the time of secondary wall deposition. Furthermore, one of the most abundant XET isoforms in secondary vascular tissues (PttXET16A) was cloned and immunolocalized to fibers at the stage of secondary wall formation. Together, these data strongly suggest that XET has a previously unreported role in restructuring primary walls at the time when secondary wall layers are deposited, probably creating and reinforcing the connections between the primary and secondary wall layers. We also observed that xylogucan is incorporated at a high level in the inner layer of nacreous walls of mature sieve tube elements.

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“…Expression patterns of genes encoding cell wall-modifying enzymes during grape berry development show increases in the expression of VvXET genes, which encode xyloglucan endotransglycosylases (XETs), post véraison (Nunan et al, 2001). In soybean (Glycine max), the BRU1 gene, which encodes a functional XET involved in expansion growth, has been shown to be induced by BRs (Zurek and Clouse, 1994;Oh et al, 1998). Thus, in grape berries, the high BR levels during véraison (Fig.…”

Section: Brs Influence the Onset Of Ripening In Grape Berriesmentioning

confidence: 99%

Grapes on Steroids. Brassinosteroids Are Involved in Grape Berry Ripening

et al. 2005

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Fruit ripening is a unique plant developmental process with direct implications for our food supply, nutrition, and health. In contrast to climacteric fruit, where ethylene is pivotal, the hormonal control of ripening in nonclimacteric fruit, such as grape (Vitis vinifera), is poorly understood. Brassinosteroids (BRs) are steroidal hormones, essential for normal plant growth and development but not previously implicated in the ripening of nonclimacteric fruit. Here we show that increases in endogenous BR levels, but not indole-3-acetic acid (IAA) or GA levels, are associated with ripening in grapes. Putative grape homologs of genes encoding BR biosynthesis enzymes (BRASSINOSTEROID-6-OXIDASE and DWARF1) and the BR receptor (BRASSINOSTEROID INSENSITIVE 1) were isolated, and the function of the grape BRASSINOSTEROID-6-OXIDASE gene was confirmed by transgenic complementation of the tomato (Lycopersicon esculentum) extreme dwarf (d x /d x ) mutant. Expression analysis of these genes during berry development revealed transcript accumulation patterns that were consistent with a dramatic increase in endogenous BR levels observed at the onset of fruit ripening. Furthermore, we show that application of BRs to grape berries significantly promoted ripening, while brassinazole, an inhibitor of BR biosynthesis, significantly delayed fruit ripening. These results provide evidence that changes in endogenous BR levels influence this key developmental process. This may provide a significant insight into the mechanism controlling ripening in grapes, which has direct implications for the logistics of grape production and down-stream processing.

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Soybean BRU1 Encodes a Functional Xyloglucan Endotransglycosylase That is Highly Expressed in Inner Epicotyl Tissues during Brassinosteroid-Promoted Elongation

Cited by 76 publications

References 0 publications

A Putative Role for the Tomato Genes DUMPY and CURL-3 in Brassinosteroid Biosynthesis and Response

A Putative Role for the Tomato Genes DUMPY and CURL-3 in Brassinosteroid Biosynthesis and Response

Xyloglucan Endotransglycosylases Have a Function during the Formation of Secondary Cell Walls of Vascular Tissues

Grapes on Steroids. Brassinosteroids Are Involved in Grape Berry Ripening

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