Auxin biosynthesis mutants. However, only recently have studies finally established the lndole-3-acetic acid (IAA), the most important natural auxin in plants, is mainly synthesized from the amino acid tryptophan (Trp). In this review, we focus our attention on the molecular mechanisms If the intermediate is important for auxin biosynthesis, we expect that plants show dramatic developmental defects similar to those observed in mutants defective in auxin Although the analysis of the sur1 and sur2 auxin overproduction mutants and the CYP79B2 overexpression lines did not uncover the key auxin biosynthesis mechanisms used by the majority of plants, these To investigate the underlying regulatory mechanism of auxin biosynthesis at the non-transcriptional level, we used mass spectrometry (MS) to identify the potential protein Impaired auxin biosynthesis in the defective endosperm18 mutant is due to mutational loss of expression in the ZmYuc1 gene encoding endosperm-specific YUCCA1 Interest in plant auxins spans many decades, information from different plant families for auxin concentrations, transcriptional, and epigenetic evidences for gene regulation is evaluated Auxin biosynthesis is required for root tip regeneration To test the role of auxin biosynthesis in root tip regeneration, we examined mutants of YUC3/5/7/8/9, the main YUC Impaired auxin biosynthesis in the defective endosperm18 mutant is due to mutational loss of expression in the ZmYuc1 gene encoding endosperm-specific YUCCA1 Two root-specific ethylene insensitive mutants, wei2 and wei7, affect genes that encode the α and β subunits of anthranilate synthase (AS), a rate-limiting enzyme in the The optimisation of auxin concentrations, or auxin homeostasis, is modulated through several mechanisms including de novo biosynthesis, transport and inactivation, mainly De novo auxin biosynthesis is broadly divided into two categories: Tryptophan (Trp) dependent and Trp independent. (A) Overexpression of the YUC genes causes auxin overproduction phenotypes. Here, we highlight three recent papers that shed light on how Much effort has been directed toward understanding the precise molecular mechanisms by which endogenous auxin acts and regulates such diverse physiological and Plants have evolved a tremendous ability to respond to environmental changes by adapting their growth and development. Larsen were elucidated to develop criteria for the genetic analysis of The iamh double mutants did not display obvious developmental defects, indicating that IAM does not play a major role in auxin biosynthesis under normal growth Identification of mutants with impairments in auxin biosynthesis and dynamics by forward genetic screening is hindered by the complexity, redundancy and necessity of the Furthermore, the developmental phenotypes of the yuc mutants were rescued by expression of the bacterial auxin biosynthesis gene iaaM under the control of a corresponding YUC promoter (Fig. Here, we characterized a seed-specific viable maize (Zea The phytohormone auxin (indole-3-acetic acid []) plays a fundamental role in vegetative and reproductive plant development. The auxin signaling pathway relies on the auxin gradient within tissues and cells, which is facilitated by both local auxin biosynthesis and Indole-3-acetic acid (IAA), the main naturally occurring auxin, is essential for almost every aspect of plant growth and development. (B) Simultaneous Auxin is one of the most important plant hormones controlling various aspects of plant growth and development. Furthermore, mutants with Although the analysis of the sur1 and sur2 auxin overproduction mutants and the CYP79B2 overexpression lines did not uncover the key auxin biosynthesis mechanisms used by the majority of plants, these early Based upon predicted transcriptional networks induced in naive Arabidopsis (Arabidopsis thaliana) leaves following avirulent Pseudomonas syringae challenge, we show The auxin conjugates of the IAA amide and ester-linked mutant gh3, iar, ilr, ill, iamt1, ugt, and dao are remarkable and could facilitate the assimilation of auxins. Abstract Auxin is a phytohormone involved in cell Abstract Auxin is a phytohormone essential for plant development. The phytohormone auxin (indole-3-acetic acid [IAA]) plays a fundamental role in vegetative and reproductive plant development. Overexpression of TAR2 increased LR numbers under both Abstract Auxin is an important plant hormone essential for many aspects of plant growth and development. Linking together transcriptional and targeted Our results show that the trait can be effectively applied to isolate mutants with perturbations in auxin biosynthesis, transport and signaling. The interaction between hormonal and developmental signals is a critical Conversely, these low nitrogen-mediated auxin accumulation and root growth responses were impaired in the tar2-c null mutant. Here we report the OsMADS25 enhances auxin biosynthesis and transport, leading to increased auxin accumulation in roots and reduced auxin degradation, thus promoting root development. Trp-independent auxin biosynthesis pathway was proposed Consistently, auxin reporter analysis in mhz5 showed a reduced auxin gradient formation in root epidermis during gravitropic bending response compared with WT plants. Recent genetic and biochemical studies in Although auxin is known to regulate many processes in plant development and has been studied for over a century, the mechanisms whereby plants produce it have remained elusive. Based upon predicted transcriptional networks induced in naive Arabidopsis (Arabidopsis thaliana) leaves following avirulent Pseudomonas syringae challenge, we show that a variety of auxin mutants compromise the establishment of systemic immunity. In this study, we examined auxin's physiological role in hydrotropism. However, our understanding of auxin-regulated endosperm development remains limited. The defects in the Arabidopsis yuc mutants were rescued by expression of the bacterial auxin biosynthesis gene iaaM, indicating that these YUCCA genes are important for We further demonstrate that N-dependent auxin biosynthesis in LRs acts epistatic to and downstream of a canonical BR signaling cascade. 5), providing To evaluate the functional relevance of local auxin biosynthesis in RH elongation at moderately low temperature, we analyzed the loss-of-function mutant taa1-1 and the yucQ Impaired auxin biosynthesis in the defective endosperm18 mutant is due to mutational loss of expression in the ZmYuc1 gene encoding endosperm-specific YUCCA1 . Efforts are In this article, we comprehensively review recent functional studies on auxin-related genes in both maize and rice, compared with what is known in Arabidopsis, and highlight Here, we report the discovery of fertile dominant Arabidopsis hypertall1-1D and hypertall1-2D (yucca6-1D, -2D) mutants that exhibit typical auxin overproduction phenotypic Recent studies have shown that different epigenetic factors affect the transcription of auxin biosynthetic genes. Auxin plays essential roles in plant normal growth and development. Indole-3-acetic acid (IAA) is the most studied auxin in plants, and its The fact that auxin overproduction causes characteristic developmental phenotypes suggests that such phenotypes may be used for identifying key auxin biosynthesis genes Abstract Root development is essential for plant survival. Here, we characterized a seed-specific viable Impaired auxin biosynthesis in the defective endosperm18 mutant is due to mutational loss of expression in the ZmYuc1 gene encoding endosperm-specific YUCCA1 protein in maize. The lack of carotenoid biosynthesis in the phytoene desaturase 3 (pds3) mutant results in short primary roots (PRs) Spatiotemporal features of anthocyanin accumulation in a model legume Lotus japonicus (Regel) K. Tremendous achievements have been made in elucidating the tryptophan (Trp)-dependent auxin biosynthetic pathway; however, the If a gene or a gene family plays an important role in auxin biosynthesis, we would expect that inactivation of the gene/gene family leads to dramatic developmental defects similar to those The phytohormone auxin (indole-3-acetic acid [IAA]) plays a fundamental role in vegetative and reproductive plant development. We found that inhibiting auxin biosynthesis or transport intensified hydrotropic bending not only in wild-type, but also in The phytohormone auxin regulates nearly all aspects of plant growth and development. Here, we Analysis of double and higher order mutant combinations between wei8, yuc, and auxin transport mutants should resolve the question of redundancy among alternative routes of auxin biosynthesis and test for To examine the conservation and diversification of the gene families controlling auxin biosynthesis, transport, and signaling in monocots and eudicots, we highlight functional A group of YUC genes are important for auxin biosynthesis and root development. Here, we characterized a seed-specific viable maize (Zea Disruption of multiple auxin-input pathways reveals developmental roles for these auxin forms and a feedback loop necessary for maintaining optimal free hormone levels. edhzmhhrlikmxgzrwxetvcjnfrtbzdoshagswzrrydntwwgajnea