Transcriptome profiling of Arabidopsis tac1 and lazy1 mutant shoot tips under normal and gravistimulated conditions
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ABSTRACT: This data is was generated in connection with a study on the 'Opposing influences of TAC1 and LAZY1 on Lateral Shoot Orientation in Arabidopsis'. RNA was extracted from individual shoot tips from wild type (Columbia; Col), tac1, and lazy1 plants that experienced either 0 or 45 minutes of gravistimulation by 90-degree reorientation. The summary of the entire project is as follows: 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.
Project description:Prunus persica (peach) trees carrying the ‘Pillar’ or ‘Broomy’ trait (br) have vertically oriented branches caused by loss of function mutations in a gene called TILLER ANGLE CONTROL 1 (TAC1). TAC1 encodes a protein in the IGT gene family that includes LAZY1 and DEEPER ROOTING 1 (DRO1), which regulat lateral branch and root orientations, respectively. Here, we found that some of the native TAC1 alleles in the hexaploid plum species Prunus domestica, which has a naturally more upright stature, contained a variable length trinucleotide repeat within the same exon 3 region previously found to be disrupted in pillar peach trees. RNAi silencing of TAC1 in plum resulted in trees with severely vertical branch orientations similar to those in pillar peaches but with an even narrower profile. In contrast, PpeTAC1 over-expression in plum led to trees with wider branch angles and more horizontal branch orientations. Pillar peach trees and transgenic plum lines exhibited pleiotropic phenotypes including differences in trunk and branch diameter, stem growth, and twisting branch phenotypes. Expression profiling of pillar peach trees revealed differential expression of numerous genes associated with biotic and abiotic stress, hormone responses, plastids, reactive oxygen, and secondary and cell wall metabolism. Collectively, the data provide important clues for understanding TAC1 function and show that alteration of TAC1 expression may have broad applicability to agricultural and ornamental tree industries.
Project description:Trees with weeping shoot architectures are valued for their beauty and are a resource for understanding how plants regulate posture control. The Prunus persica (peach) weeping phenotype, which has elliptical downward arching branches, is caused by a homozygous mutation in the WEEP gene. Until now, little was known about the function of WEEP protein despite its high conservation throughout Plantae. Here, we present the results of anatomical, biochemical, biomechanical, physiological, and molecular experiments that provide insight into WEEP function. Our data suggest that weeping peach trees do not have defects in branch structure. Rather, transcriptomes from the adaxial (upper) and abaxial (lower) sides of standard and weeping branch shoot tips revealed flipped expression patterns for genes associated with early auxin response, tissue patterning, cell elongation, and tension wood development. This suggests that WEEP promotes polar auxin transport toward the lower side during shoot gravitropic response, leading to cell elongation and tension wood development. In addition, weeping peach trees exhibited steeper root systems and faster lateral root gravitropic response. This suggests that WEEP moderates root gravitropism and is essential to establishing the set-point angle of lateral roots from the gravity vector. Additionally, size-exclusion chromatography indicated that WEEP proteins self-oligomerize, like other proteins with sterile alpha motif domains. Collectively, our results from weeping peach provide new insight into polar auxin transport mechanisms associated with gravitropism and lateral shoot and root orientation.
Project description: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 Prunus persica (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, Ppa013325, having a 1.8-Kb deletion spanning the 5′ end. This gene, dubbed WEEP, 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 Prunus domestica (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 per- ception 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.
Project description:Purpose: found out the regulated genes of nulliplex-branch and its forming molecular mechanism Methods: the GhBRC1 genes of nulliplex branch and short branch cotton are silenced by VIGS, and then the shoot apical mRNA of controls and treated were sequenced, in four repeats, using Illumina HiSeq 2000. Results: we found 3519 and 17 differnent expressed genes in nulliplex-branch and short branch cotton, respectively. Conclusions: Our study represents the genes control development of lateral branch.
Project description:Purpose: found out the regulated genes of nulliplex-branch and its forming molecular mechanism Methods: shoot apical mRNA and miRNA in two nulliplex branch and two normal branch cotton of three development stages were generated by deep sequencing, in triplicate, using Illumina HiSeq 2000. Results: we found 3 825 and 353 specific stage differnent expressed genes in pre-budding stage of island cotton and upland cotton, respectively. In miRNA, we found 16 and 18 specific stage differnent expressed miRNA in pre-budding stageof island cotton and upland cotton, respectively. Conclusions: Our study represents the genes and miRNA control development of lateral branch and regulate flowering time at same times. Shoot apical mRNA and miRNA of normal branch cotton and nulliplex branch botton were generated by deep sequencing, in triplicate, using Illumina HiSeq 2000.
Project description:The Arabidopsis thaliana transcription factor LATERAL ORGAN BOUNDARIES (LOB) is expressed in the boundary between the shoot apical meristem and initiating lateral organs. To identify genes regulated by LOB activity, we used an inducible 35S:LOB-GR line. This analysis identified genes that are differentially expressed in response to ectopic LOB activity. 35S:LOB-GR and Col wild-type seedlings were treated with dexamethasone (DEX) or mock-treated. Three biological replicates were conducted for each treatment.
Project description:We study differences in gene expression between Populus P35S::PLGT , RNAi_PLGT and control/WT plants, affecting tropic responses and stem development. We used microarrays to detail the global program of gene expression underlying morphological and developmental changes droved by th etransgenic manipulations of PLGT gene. By screening activation tagging population we identified the PLAGIOTROPICA (PLGT) mutant. The mutant is severely impaired in gravitropic responses and displays consistent south orientation of the shoot tip in the overexpressing plants. We positioned the tag, localized a putative candidate gene and verified transcription activation. The activated gene encodes an ortholog of the OCTOPUS gene from Arabidopsis. We fully recapitulated the phenotype by overexpression of the gene into the same genotype under strong constitutive promoter (P35S::PLGT). We further downregulated the gene using RNAi approach. The gene was most highly expressed in young stems and phloem tissues.
Project description:Purpose: found out the regulated genes of nulliplex-branch and its forming molecular mechanism Methods: shoot apical mRNA and miRNA in two nulliplex branch and two normal branch cotton of three development stages were generated by deep sequencing, in triplicate, using Illumina HiSeq 2000. Results: we found 3 825 and 353 specific stage differnent expressed genes in pre-budding stage of island cotton and upland cotton, respectively. In miRNA, we found 16 and 18 specific stage differnent expressed miRNA in pre-budding stageof island cotton and upland cotton, respectively. Conclusions: Our study represents the genes and miRNA control development of lateral branch and regulate flowering time at same times.
Project description:Proteins from plant shoot and root tissues were extracted from wild-type Arabidopsis thaliana ecotype Columbia (Col-0). They were enriched on conditioned U(VI)-loaded and U(VI)-free Duolite C467 beads. The enriched proteins were identified and quantified by label-free shotgun proteomics.