Expression Patterns and Functional Characterisation of Arabidopsis GALACTOSE OXIDASE-LIKE (GOXL) Genes Suggest Specialised Roles for Galactose Oxidases in Plants

Author(s):  
Krešimir Šola ◽  
Gillian H Dean ◽  
Yi Li ◽  
Julia Lohmann ◽  
Mahsa Movahedan ◽  
...  

Abstract Galactose oxidases (GalOxs) are well-known enzymes that have been identified in several fungal species and characterised using structural and enzymatic approaches. However, until very recently, almost no information on their biological functions was available. The Arabidopsis (Arabidopsis thaliana) gene RUBY PARTICLES IN MUCILAGE (RUBY) encodes a putative plant GalOx that is required for pectin cross-linking through modification of galactose (Gal) side-chains and promotes cell-cell adhesion between seed coat epidermal cells. RUBY is one member of a family of seven putative GalOxs encoded in the Arabidopsis genome. To examine the function(s) of GalOxs in plants, we studied the remaining six GALACTOSE OXIDASE-LIKE (GOXL) proteins. Like RUBY, four of these proteins (GOXL1, 3, 5 and 6) were found to localize primarily to the apoplast, while GOXL2 and 4 were found primarily in the cytoplasm. Complementation and GalOx assay data suggested that GOXL1, GOXL3, and possibly GOXL6 have similar biochemical activity to RUBY, whereas GOXL5 only weakly complemented, and GOXL2 and GOXL4 showed no activity. Members of this protein family separated into four distinct clades prior to the divergence of the angiosperms. There have been recent duplications in Brassicaceae resulting in two closely related pairs of genes that have either retained similarity in expression (GOXL1 and GOXL6) or show expression divergence (GOXL3 and RUBY). Mutant phenotypes were not detected when these genes were disrupted, but their expression patterns suggest that these proteins may function in tissues that require mechanical reinforcements in the absence of lignification.

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 249
Author(s):  
Weimiao Liu ◽  
Liai Xu ◽  
Hui Lin ◽  
Jiashu Cao

The growth of plant cells is inseparable from relaxation and expansion of cell walls. Expansins are a class of cell wall binding proteins, which play important roles in the relaxation of cell walls. Although there are many members in expansin gene family, the functions of most expansin genes in plant growth and development are still poorly understood. In this study, the functions of two expansin genes, AtEXPA4 and AtEXPB5 were characterized in Arabidopsis thaliana. AtEXPA4 and AtEXPB5 displayed consistent expression patterns in mature pollen grains and pollen tubes, but AtEXPA4 also showed a high expression level in primary roots. Two single mutants, atexpa4 and atexpb5, showed normal reproductive development, whereas atexpa4atexpb5 double mutant was defective in pollen tube growth. Moreover, AtEXPA4 overexpression enhanced primary root elongation, on the contrary, knocking out AtEXPA4 made the growth of primary root slower. Our results indicated that AtEXPA4 and AtEXPB5 were redundantly involved in pollen tube growth and AtEXPA4 was required for primary root elongation.


Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 721-731 ◽  
Author(s):  
Teresa D Shippy ◽  
Jianhua Guo ◽  
Susan J Brown ◽  
Richard W Beeman ◽  
Robin E Denell

Abstract The Tribolium castaneum homeotic gene maxillopedia (mxp) is the ortholog of Drosophila proboscipedia (pb). Here we describe and classify available mxp alleles. Larvae lacking all mxp function die soon after hatching, exhibiting strong transformations of maxillary and labial palps to legs. Hypomorphic mxp alleles produce less severe transformations to leg. RNA interference with maxillopedia double-stranded RNA results in phenocopies of mxp mutant phenotypes ranging from partial to complete transformations. A number of gain-of-function (GOF) mxp alleles have been isolated based on transformations of adult antennae and/or legs toward palps. Finally, we have characterized the mxp expression pattern in wild-type and mutant embryos. In normal embryos, mxp is expressed in the maxillary and labial segments, whereas ectopic expression is observed in some GOF variants. Although mxp and Pb display very similar expression patterns, pb null embryos develop normally. The mxp mutant larval phenotype in Tribolium is consistent with the hypothesis that an ancestral pb-like gene had an embryonic function that was lost in the lineage leading to Drosophila.


Author(s):  
Zhen Tian ◽  
Xiaodong Qin ◽  
Hui Wang ◽  
Ji Li ◽  
Jinfeng Chen

AbstractThe CONSTANS-like (COL) gene family is one of the plant-specific transcription factor families that play important roles in plant growth and development. However, the knowledge of COLs related in cucumber is limited, and their biological functions, especially in the photoperiod-dependent flowering process, are still unclear. In this study, twelve CsaCOL genes were identified in the cucumber genome. Phylogenetic and conserved motif analyses provided insights into the evolutionary relationship between the CsaCOLs. Further, the comparative genome analysis revealed that COL genes are conserved in different plant species, especially collinearity gene pairs related to CsaCOL5. Ten kinds of cis-acting elements were vividly detected in CsaCOLs promoter regions, including five light-responsive elements, which echo the diurnal rhythm expression patterns of seven CsaCOL genes under SD and LD photoperiod regimes. Combined with the expression data of developmental stage, three CsaCOL genes are involved in the flowering network and play pivotal roles for the floral induction process. Our results provide useful information for further elucidating the structural characteristics, expression patterns, and biological functions of COL family genes in many plants


2019 ◽  
Vol 20 (23) ◽  
pp. 5933 ◽  
Author(s):  
Yuanyuan Jiang ◽  
Jiangrong Peng ◽  
Zhike Zhang ◽  
Shoukai Lin ◽  
Shunquan Lin ◽  
...  

Flowering plants have evolved different flowering habits to sustain long-term reproduction. Most woody trees experience dormancy and then bloom in the warm spring, but loquat blooms in the cold autumn and winter. To explore its mechanism of flowering regulation, we cloned two SHORT VEGETATIVE PHASE (SVP) homologous genes from ‘Jiefanzhong’ loquat (Eriobotrya japonica Lindl.), namely, EjSVP1 and EjSVP2. Sequence analysis revealed that the EjSVPs were typical MADS-box transcription factors and exhibited a close genetic relationship with other plant SVP/DORMANCY-ASSOCIATED MADS-BOX (DAM) proteins. The temporal and spatial expression patterns showed that EjSVP1 and EjSVP2 were mainly expressed in the shoot apical meristem (SAM) after the initiation of flowering; after reaching their highest level, they gradually decreased with the development of the flower until they could not be detected. EjSVP1 expression levels were relatively high in young tissues, and EjSVP2 expression levels were relatively high in young to mature transformed tissues. Interestingly, EjSVP2 showed relatively high expression levels in various flower tissues. We analyzed the EjSVP promoter regions and found that they did not contain the C-repeat/dehydration-responsive element. Finally, we overexpressed the EjSVPs in wild-type Arabidopsis thaliana Col-0 and found no significant changes in the number of rosette leaves of Arabidopsis thaliana; however, overexpression of EjSVP2 affected the formation of Arabidopsis thaliana flower organs. In conclusion, EjSVPs were found to play an active role in the development of loquat flowering. These findings may provide a reference for exploring the regulation mechanisms of loquat flowering and the dormancy mechanisms of other plants.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2169
Author(s):  
Hailian Zhou ◽  
Jiaying Li ◽  
Xueyuan Liu ◽  
Xiaoshuang Wei ◽  
Ziwei He ◽  
...  

Bcl-2-associated athanogene (BAG), a group of proteins evolutionarily conserved and functioned as co-chaperones in plants and animals, is involved in various cell activities and diverse physiological processes. However, the biological functions of this gene family in rice are largely unknown. In this study, we identified a total of six BAG members in rice. These genes were classified into two groups, OsBAG1, -2, -3, and -4 are in group I with a conserved ubiquitin-like structure and OsBAG5 and -6 are in group Ⅱ with a calmodulin-binding domain, in addition to a common BAG domain. The BAG genes exhibited diverse expression patterns, with OsBAG4 showing the highest expression level, followed by OsBAG1 and OsBAG3, and OsBAG6 preferentially expressed in the panicle, endosperm, and calli. The co-expression analysis and the hierarchical cluster analysis indicated that the OsBAG1 and OsBAG3 were co-expressed with primary cell wall-biosynthesizing genes, OsBAG4 was co-expressed with phytohormone and transcriptional factors, and OsBAG6 was co-expressed with disease and shock-associated genes. β-glucuronidase (GUS) staining further indicated that OsBAG3 is mainly involved in primary young tissues under both primary and secondary growth. In addition, the expression of the BAG genes under brown planthopper (BPH) feeding, N, P, and K deficiency, heat, drought and plant hormones treatments was investigated. Our results clearly showed that OsBAGs are multifunctional molecules as inferred by their protein structures, subcellular localizations, and expression profiles. BAGs in group I are mainly involved in plant development, whereas BAGs in group II are reactive in gene regulations and stress responses. Our results provide a solid basis for the further elucidation of the biological functions of plant BAG genes.


2021 ◽  
Vol 2 ◽  
Author(s):  
Adrienne H. K. Roeder

Abstract During development, Arabidopsis thaliana sepal primordium cells grow, divide and interact with their neighbours, giving rise to a sepal with the correct size, shape and form. Arabidopsis sepals have proven to be a good system for elucidating the emergent processes driving morphogenesis due to their simplicity, their accessibility for imaging and manipulation, and their reproducible development. Sepals undergo a basipetal gradient of growth, with cessation of cell division, slow growth and maturation starting at the tip of the sepal and progressing to the base. In this review, I discuss five recent examples of processes during sepal morphogenesis that yield emergent properties: robust size, tapered tip shape, laminar shape, scattered giant cells and complex gene expression patterns. In each case, experiments examining the dynamics of sepal development led to the hypotheses of local rules. In each example, a computational model was used to demonstrate that these local rules are sufficient to give rise to the emergent properties of morphogenesis.


2020 ◽  
Vol 21 (19) ◽  
pp. 7404
Author(s):  
Yanqiao Zhu ◽  
Oliver Berkowitz ◽  
Jennifer Selinski ◽  
Andreas Hartmann ◽  
Reena Narsai ◽  
...  

Seed germination is a critical process for completion of the plant life cycle and for global food production. Comparing the germination transcriptomes of barley (Hordeum vulgare) to Arabidopsis thaliana revealed the overall pattern was conserved in terms of functional gene ontology; however, many oppositely responsive orthologous genes were identified. Conserved processes included a set of approximately 6000 genes that peaked early in germination and were enriched in processes associated with RNA metabolism, e.g., pentatricopeptide repeat (PPR)-containing proteins. Comparison of orthologous genes revealed more than 3000 orthogroups containing almost 4000 genes that displayed similar expression patterns including functions associated with mitochondrial tricarboxylic acid (TCA) cycle, carbohydrate and RNA/DNA metabolism, autophagy, protein modifications, and organellar function. Biochemical and proteomic analyses indicated mitochondrial biogenesis occurred early in germination, but detailed analyses revealed the timing involved in mitochondrial biogenesis may vary between species. More than 1800 orthogroups representing 2000 genes displayed opposite patterns in transcript abundance, representing functions of energy (carbohydrate) metabolism, photosynthesis, protein synthesis and degradation, and gene regulation. Differences in expression of basic-leucine zippers (bZIPs) and Apetala 2 (AP2)/ethylene-responsive element binding proteins (EREBPs) point to differences in regulatory processes at a high level, which provide opportunities to modify processes in order to enhance grain quality, germination, and storage as needed for different uses.


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