Developmental characterization of the fasciated locus and mapping of Arabidopsis candidate genes involved in the control of floral meristem size and carpel number in tomato

Genome ◽  
2006 ◽  
Vol 49 (8) ◽  
pp. 991-1006 ◽  
Author(s):  
L S Barrero ◽  
B Cong ◽  
F Wu ◽  
S D Tanksley

Mutation at the fasciated locus was a key step in the production of extreme fruit size during tomato domestication. To shed light on the nature of these changes, near-isogenic lines were used for a comparative developmental study of fasciated and wild-type tomato plants. The fasciated gene directly affects floral meristem size and is expressed before the earliest stages of flower organogenesis. As a result, mature fruit of fasciated mutants have more carpels (locules) and greater fruit diameter and mass. The discovery that fasciated affects floral meristem size led to a search for candidate genes from Arabidopsis known to be involved in floral meristem development. Putative homologs were identified in a large tomato EST database, verified through phylogenetic analyses, and mapped in tomato; none mapped to the fasciated locus; however, putative homologs of WUS and WIG mapped to the locule number locus on chromosome 2, the second major transition to large tomato fruit, with WUS showing the highest association. In other cases, minor QTLs for floral organ number (lcn2.2) and (stn11.2) co-localized with a CLV1 paralog and with the syntenic region containing the CLV3 gene in Arabidopsis, respectively.Key words: fasciated, floral meristem, locule number, Arabidopsis, fruit.


2020 ◽  
Vol 117 (14) ◽  
pp. 8187-8195 ◽  
Author(s):  
Fernando J. Yuste-Lisbona ◽  
Antonia Fernández-Lozano ◽  
Benito Pineda ◽  
Sandra Bretones ◽  
Ana Ortíz-Atienza ◽  
...  

A dramatic evolution of fruit size has accompanied the domestication and improvement of fruit-bearing crop species. In tomato (Solanum lycopersicum), naturally occurring cis-regulatory mutations in the genes of the CLAVATA-WUSCHEL signaling pathway have led to a significant increase in fruit size generating enlarged meristems that lead to flowers with extra organs and bigger fruits. In this work, by combining mapping-by-sequencing and CRISPR/Cas9 genome editing methods, we isolatedEXCESSIVE NUMBER OF FLORAL ORGANS(ENO), an AP2/ERF transcription factor which regulates floral meristem activity. Thus, theENOgene mutation gives rise to plants that yield larger multilocular fruits due to an increased size of the floral meristem. Genetic analyses indicate thatenoexhibits synergistic effects with mutations at theLOCULE NUMBER(encodingSlWUS) andFASCIATED(encodingSlCLV3) loci, two central players in the evolution of fruit size in the domestication of cultivated tomatoes. Our findings reveal that anenomutation causes a substantial expansion ofSlWUSexpression domains in a flower-specific manner. In vitro binding results show that ENO is able to interact with the GGC-box cis-regulatory element within theSlWUSpromoter region, suggesting that ENO directly regulatesSlWUSexpression domains to maintain floral stem-cell homeostasis. Furthermore, the study of natural allelic variation of theENOlocus proved that a cis-regulatory mutation in the promoter ofENOhad been targeted by positive selection during the domestication process, setting up the background for significant increases in fruit locule number and fruit size in modern tomatoes.



Genetics ◽  
2001 ◽  
Vol 158 (1) ◽  
pp. 413-422 ◽  
Author(s):  
Zachary Lippman ◽  
Steven D Tanksley

Abstract In an effort to determine the genetic basis of exceptionally large tomato fruits, QTL analysis was performed on a population derived from a cross between the wild species Lycopersicon pimpinellifolium (average fruit weight, 1 g) and the L. esculentum cultivar var. Giant Heirloom, which bears fruit in excess of 1000 g. QTL analysis revealed that the majority (67%) of phenotypic variation in fruit size could be attributed to six major loci localized on chromosomes 1-3 and 11. None of the QTL map to novel regions of the genome—all have been reported in previous studies involving moderately sized tomatoes. This result suggests that no major QTL beyond those already reported were involved in the evolution of extremely large fruit. However, this is the first time that all six QTL have emerged in a single population, suggesting that exceptionally large-fruited varieties, such as Giant Heirloom, are the result of a novel combination of preexisting QTL alleles. One of the detected QTL, fw2.2, has been cloned and exerts its effect on fruit size through global control of cell division early in carpel/fruit development. However, the most significant QTL detected in this study (fw11.3, lcn11.1) maps to the bottom of chromosome 11 and seems to exert its effect on fruit size through control of carpel/locule number. A second major locus, also affecting carpel number (and hence fruit size), was mapped to chromosome 2 (fw2.1, lcn2.1). We propose that these two carpel number QTL correspond to the loci described by early classical geneticists as fasciated (f) and locule number (lc), respectively.



Botany ◽  
2018 ◽  
Vol 96 (12) ◽  
pp. 883-895 ◽  
Author(s):  
Yan Zhang ◽  
Yushun Li ◽  
Jie Zhang ◽  
Tayeb Muhammad ◽  
Yan Liang

Fruit size and shape are the primary criteria for domestication and improvement of tomato. The varying sizes and shapes of tomato fruit further signify their importance as agronomic traits. Here, we characterized a tomato mutant, smaller fruit (sf), which bears relatively small and ovoid fruits compared with the large and flat fruits of the wild-type (WT). Phenotypic measurements and histological analyses revealed that fruit diameter but not fruit length of the sf mutant decreased compared with that of the WT. This phenotypic change was attributed to significant decreases in locule number and pericarp cell layers in a transverse direction, which resulted in the transition of fruit shape from flat in the WT to ovoid in sf. Comparison of the transcriptomes of ovaries of sf with the WT using RNA-Seq identified 2596 differentially expressed genes, in which 1737 genes significantly were up-regulated and 859 genes were dramatically down-regulated in the sf ovary. Further analyses confirmed that some genes, such as CRCa, CNRs, CYCs, WUS, SUNs, OFRs, CDKs, participate in regulation of fruit size and shape of sf mutant. Thus, our study adds a new genetic resource regarding fruit size and shape of tomato, and provides a valuable basis for understanding molecular regulation of small and ovoid fruit of the sf mutant.



Plant Science ◽  
2015 ◽  
Vol 232 ◽  
pp. 41-48 ◽  
Author(s):  
Antonia Fernández-Lozano ◽  
Fernando J. Yuste-Lisbona ◽  
Fernando Pérez-Martín ◽  
Benito Pineda ◽  
Vicente Moreno ◽  
...  




2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ian S. E. Bally ◽  
◽  
Aureliano Bombarely ◽  
Alan H. Chambers ◽  
Yuval Cohen ◽  
...  

Abstract Background Mango, Mangifera indica L., an important tropical fruit crop, is grown for its sweet and aromatic fruits. Past improvement of this species has predominantly relied on chance seedlings derived from over 1000 cultivars in the Indian sub-continent with a large variation for fruit size, yield, biotic and abiotic stress resistance, and fruit quality among other traits. Historically, mango has been an orphan crop with very limited molecular information. Only recently have molecular and genomics-based analyses enabled the creation of linkage maps, transcriptomes, and diversity analysis of large collections. Additionally, the combined analysis of genomic and phenotypic information is poised to improve mango breeding efficiency. Results This study sequenced, de novo assembled, analyzed, and annotated the genome of the monoembryonic mango cultivar ‘Tommy Atkins’. The draft genome sequence was generated using NRGene de-novo Magic on high molecular weight DNA of ‘Tommy Atkins’, supplemented by 10X Genomics long read sequencing to improve the initial assembly. A hybrid population between ‘Tommy Atkins’ x ‘Kensington Pride’ was used to generate phased haplotype chromosomes and a highly resolved phased SNP map. The final ‘Tommy Atkins’ genome assembly was a consensus sequence that included 20 pseudomolecules representing the 20 chromosomes of mango and included ~ 86% of the ~ 439 Mb haploid mango genome. Skim sequencing identified ~ 3.3 M SNPs using the ‘Tommy Atkins’ x ‘Kensington Pride’ mapping population. Repeat masking identified 26,616 genes with a median length of 3348 bp. A whole genome duplication analysis revealed an ancestral 65 MYA polyploidization event shared with Anacardium occidentale. Two regions, one on LG4 and one on LG7 containing 28 candidate genes, were associated with the commercially important fruit size characteristic in the mapping population. Conclusions The availability of the complete ‘Tommy Atkins’ mango genome will aid global initiatives to study mango genetics.



1965 ◽  
Vol 43 (1) ◽  
pp. 137-146
Author(s):  
L. Butler

Fruit weights taken from two F2's of 1500 plants indicated that the genes d p o s Lc dil and suf all affect fruit weight. The recessive alleles, except suf and Lc, were associated with small fruit size. The data were analyzed to determine whether this association was the result of linkage or pleiotropic effects. The major effect occurred in the o region, which is some 44 units from the centromere of chromosome 2. The o gene makes the genes oval or pear-shaped instead of spherical, and it is shown that when the locule wall of a spherical fruit and an oval fruit are composed of the same number of cells, the spherical fruit is always heavier. Since cell number is the inherited unit of fruit size, then o is always associated with small size. A gene controlling number of locules, which affects fruit size, is also located in this section of the chromosome. The genes d and s, which are at opposite ends of the present linkage map, both appear to be linked with fruit size genes. It is suggested that these size genes lie in the hetero-chromatin which is adjacent to both ends of the linkage map. The genes dil and suf, which were produced by radiation of the same variety, appear to have pleiotropic effects on fruit size; suf increasing, and dil decreasing fruit size.



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