ON HORMONES AND WEEPING: ASYMMETRIC HORMONE DISTRIBUTION AND THE PENDULOUS GROWTH HABIT OF THE WEEPING MULBERRY, <i>MORUS ALBA</i> VAR. <i>PENDULA</i>

Reches, Shulamit; Leshem, Y.; Wurzburger, Judith

doi:10.1111/j.1469-8137.1974.tb01312.x

Cited by 5 publications

(6 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pillar peach trees (tac1 mutants) were found to have elevated auxin concentrations in their shoot tips relative to standard cultivars 36 . Further, altered Abscisic Acid (ABA) localization in branches was associated with a weeping mulberry tree architecture, and tac1 is epistatic to a weeping peach architecture 32,37 . To investigate if TAC1-or LAZY-mediated shoot orientations are associated with hormone concentrations, LC/MS/MS was performed on extracts from Arabidopsis tac1, lazy1, and Col shoot tips, stems (just below the tip), and branch tips from plants ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Opposing influences of TAC1 and LAZY1 on Lateral Shoot Orientation in Arabidopsis

Hollender

Hill

Waite

et al. 2020

Sci Rep

View full text Add to dashboard Cite

TAC1 and LAZY1 are members of a gene family that regulates lateral shoot orientation in plants. TAC1 promotes outward orientations in response to light, while LAZY1 promotes upward shoot orientations in response to gravity via altered auxin transport. We performed genetic, molecular, and biochemical assays to investigate possible interactions between these genes. In Arabidopsis they were expressed in similar tissues and double mutants revealed the wide-angled lazy1 branch phenotype, indicating it is epistatic to the tac1 shoot phenotype. Surprisingly, the lack of TAC1 did not influence gravitropic shoot curvature responses. Combined, these results suggest TAC1 might negatively regulate LAZY1 to promote outward shoot orientations. However, additional results revealed that TAC1-and LAZY1 influence on shoot orientation is more complex than a simple direct negative regulatory pathway. Transcriptomes of Arabidopsis tac1 and lazy1 mutants compared to wild type under normal and gravistimulated conditions revealed few overlapping differentially expressed genes. Overexpression of each gene did not result in major branch angle differences. Shoot tip hormone levels were similar between tac1, lazy1, and Col, apart from exceptionally elevated levels of salicylic acid in lazy1. The data presented here provide a foundation for future study of TAC1 and LAZY1 regulation of shoot architecture.Lateral organ orientation in both shoots and roots plays a key role in a plant's interaction with the environment and its ability to access resources such as light and water. The IGT gene family members TILLER ANGLE CONTROL 1 (TAC1) and the related set of LAZY genes are important regulators of lateral organ orientation 1,2 . These genes share four conserved amino acid regions or domains, and LAZY genes share an additional C-terminal domain 3,4 . TAC1 generally occurs as a single copy gene, but many species possess multiple LAZY genes, with six identified in Arabidopsis 2-8 . While the LAZY1 gene of Arabidopsis thaliana (Arabidopsis) contributes almost exclusively to shoot architecture, the remaining Arabidopsis LAZY genes primarily control root architecture 7,8 . However, GUS reporter activity and additive shoot phenotypes in plants with combinatorial lazy1, lazy2, and lazy4 mutations suggest LAZY2 and LAZY4 also have a role in regulating shoot orientation 7,8 . LAZY2, 3, and 4 are also known as DEEPER ROOTING (DRO3, 2, & 1) and NEGATIVE GRAVITROPIC RESPONSE OF ROOTS (NGR1, 3, & 2), respectively, as they were separately identified as regulators of lateral root orientation 6,9-12 . Further, an alternate LAZY gene nomenclature denotes LAZY3 as LZY2 and LAZY4 as LZ3Y 8 .Lateral branches, tillers, leaves, and flower buds of plants with loss-of-function tac1 mutations or reduced TAC1 expression exhibit upright orientations 3,13-19 . In contrast, lazy1 mutants have wider branch or tiller angles and lazy4/dro1 mutants display prostrate lateral root orientations 4-9,20-24 . Plants with multiple lazy/dro mutations exhibit even wider lateral shoot/root...

show abstract

Section: Resultsmentioning

confidence: 99%

Opposing influences of TAC1 and LAZY1 on Lateral Shoot Orientation in Arabidopsis

Hollender

Hill

Waite

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Likewise, GA application was reported to rescue weeping peach and cherry phenotypes via increased tension wood (24)(25)(26). Reches et al (28) found that the lower half of actively growing weeping mulberry (Morus alba Var. pendula) tree branches had significantly greater GA levels than the upper side.…”

Section: Discussionmentioning

confidence: 99%

“…To date, no causative alleles for weeping tree traits have been reported. Aberrant GA hormone concentrations and localization have been reported for a few weeping tree phenotypes, but the underlying significance of the observed differences remains unknown (24)(25)(26)(27)(28).…”

Section: Significancementioning

confidence: 99%

Loss of a highly conserved sterile alpha motif domain gene ( WEEP ) results in pendulous branch growth in peach trees

Hollender

Pascal

Tabb

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Plant shoots typically grow upward in opposition to the pull of gravity. However, exceptions exist throughout the plant kingdom. Most conspicuous are trees with weeping or pendulous branches. While such trees have long been cultivated and appreciated for their ornamental value, the molecular basis behind the weeping habit is not known. Here, we characterized a weeping tree phenotype in (peach) and identified the underlying genetic mutation using a genomic sequencing approach. Weeping peach tree shoots exhibited a downward elliptical growth pattern and did not exhibit an upward bending in response to 90° reorientation. The causative allele was found to be an uncharacterized gene,, having a 1.8-Kb deletion spanning the 5' end. This gene, dubbed , was predominantly expressed in phloem tissues and encodes a highly conserved 129-amino acid protein containing a sterile alpha motif (SAM) domain. Silencing WEEP in the related tree species (plum) resulted in more outward, downward, and wandering shoot orientations compared to standard trees, supporting a role for WEEP in directing lateral shoot growth in trees. This previously unknown regulator of branch orientation, which may also be a regulator of gravity perception or response, provides insights into our understanding of how tree branches grow in opposition to gravity and could serve as a critical target for manipulating tree architecture for improved tree shape in agricultural and horticulture applications.

show abstract

“…Plant architecture is controlled by auxin and gibberellin 3 , 4 , 6 , 26 . Auxin plays key roles in regulating meristem development and secondary growth processes.…”

Section: Discussionmentioning

confidence: 99%

“…Pendulous-stem (weeping) plants have high ornamental value during the leaf expansion period and after defoliation because of their naturally weeping stems and peculiar shape. Plants with the pendulous-branched (weeping) trait are observed in the herbaceous plant Arabidopsis 2 and many woody species, such as willow ( Salix matsudana ) 3 , Prunus persica 4 , and Morus alba 5 , 6 . However, the phenotype of weeping traits is complicated.…”

Section: Introductionmentioning

confidence: 99%

Comparative gene expression analysis reveals that multiple mechanisms regulate the weeping trait in Prunus mume

Zhang

Zheng

et al. 2021

Sci Rep

View full text Add to dashboard Cite

Prunus mume (also known as Mei) is an important ornamental plant that is popular with Asians. The weeping trait in P. mume has attracted the attention of researchers for its high ornamental value. However, the formation of the weeping trait of woody plants is a complex process and the molecular basis of weeping stem development is unclear. Here, the morphological and histochemical characteristics and transcriptome profiles of upright and weeping stems from P. mume were studied. Significant alterations in the histochemical characteristics of upright and weeping stems were observed, and the absence of phloem fibres and less xylem in weeping stems might be responsible for their inability to resist gravity and to grow downward. Transcriptome analysis showed that differentially expressed genes (DEGs) were enriched in phenylpropanoid biosynthesis and phytohormone signal transduction pathways. To investigate the differential responses to hormones, upright and weeping stems were treated with IAA (auxin) and GA3 (gibberellin A3), respectively, and the results revealed that weeping stems had a weaker IAA response ability and reduced upward bending angles than upright stems. On the contrary, weeping stems had increased upward bending angles than upright stems with GA3 treatment. Compared to upright stems, interestingly, DEGs associated with diterpenoid biosynthesis and phenylpropanoid biosynthesis were significantly enriched after being treated with IAA, and expression levels of genes associated with phenylpropanoid biosynthesis, ABC transporters, glycosylphosphatidylinositol (GPI)—anchor biosynthesis were altered after being treated with GA3 in weeping stems. Those results reveal that multiple molecular mechanisms regulate the formation of weeping trait in P. mume, which lays a theoretical foundation for the cultivation of new varieties.

show abstract

ON HORMONES AND WEEPING: ASYMMETRIC HORMONE DISTRIBUTION AND THE PENDULOUS GROWTH HABIT OF THE WEEPING MULBERRY, MORUS ALBA VAR. PENDULA

Cited by 5 publications

References 9 publications

Opposing influences of TAC1 and LAZY1 on Lateral Shoot Orientation in Arabidopsis

Opposing influences of TAC1 and LAZY1 on Lateral Shoot Orientation in Arabidopsis

Loss of a highly conserved sterile alpha motif domain gene ( WEEP ) results in pendulous branch growth in peach trees

Comparative gene expression analysis reveals that multiple mechanisms regulate the weeping trait in Prunus mume

Contact Info

Product

Resources

About