Fleshy fruit expansion and ripening are regulated by the Tomato SHATTERPROOF gene TAGL1.
The maturation and ripening of fleshy fruits is a developmental program that synchronizes seed maturation with metabolism, rendering fruit tissues desirable to seed dispersing organisms. Through RNA interference repression, we show that Tomato AGAMOUS-LIKE1 (TAGL1), the tomato (Solanum lycopersicum) ortholog of the duplicated SHATTERPROOF (SHP) MADS box genes of Arabidopsis thaliana, is necessary for fruit ripening. Tomato plants with reduced TAGL1 mRNA produced yellow-orange fruit with reduced carotenoids and thin pericarps. These fruit are also decreased in ethylene, indicating a comprehensive inhibition of maturation mediated through reduced ACC Synthase 2 expression. Furthermore, ectopic expression of TAGL1 in tomato resulted in expansion of sepals and accumulation of lycopene, supporting the role of TAGL1 in ripening. In Arabidopsis, the duplicate SHP1 and SHP2 MADS box genes regulate the development of separation layers essential for pod shatter. Expression of TAGL1 in Arabidopsis failed to completely rescue the shp1 shp2 mutant phenotypes, indicating that TAGL1 has evolved distinct molecular functions compared with its Arabidopsis counterparts. These analyses demonstrate that TAGL1 plays an important role in regulating both fleshy fruit expansion and the ripening process that together are necessary to promote seed dispersal of fleshy fruit. From this broad perspective, SHP1/2 and TAGL1, while distinct in molecular function, regulate similar activities via their necessity for seed dispersal in Arabidopsis and tomato, respectively.
Vrebalov
Julia
J
Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York 14853, USA.
Pan
Irvin L
IL
Arroyo
Antonio Javier Matas
AJ
McQuinn
Ryan
R
Chung
Miyoung
M
Poole
Mervin
M
Rose
Jocelyn
J
Seymour
Graham
G
Grandillo
Silvana
S
Giovannoni
James
J
Irish
Vivian F
VF
D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D005030:Ethylenes / Q000494:pharmacology; D005638:Fruit / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017403:In Situ Hybridization; D018551:Solanum lycopersicum / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D026161:MADS Domain Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D029681:Arabidopsis Proteins; D005030:Ethylenes; D026161:MADS Domain Proteins; D010940:Plant Proteins; D012337:RNA, Ribosomal, 18S; C419044:SHP1 protein, Arabidopsis; C419045:SHP2 protein, Arabidopsis; C036216:ethylene