Tomato 14-3-3 Genes
14-3-3 gene
GenBank
No. of ESTs at TIGR
Main expression
 TIGR TC No.
TFT1
X95900
47
Elicitor
99368 & 99369
TFT2
X95901
25
Pollen
98834
TFT3
X95902
30
Seed/Fruit
98836
TFT4
AJ504807
42
Shoot/Root
98629
TFT5
X95903
80
Fruit/Root/Tissue Culture
98835
TFT6
X95904
43
Callus/Buds
98837
TFT7
X95905
60
Callus/Fruit
99225
TFT8
X98864
10
N/A
102006
TFT9
X98865
53
Fruit/Root/Tissue Culture
99262
TFT10
X98866
35
Tissue Culture/Fruit
99498
TFT11
-
8
N/A
98628
TFT12
-
2
Flower/Pollen
99263
DFCI Tomato Gene Index
Database release 8.0 - 1st June 2002
Link to tomato 14-3-3 protein sequences


Tomato 14-3-3 Gene Expression
We have identified the twelve tomato 14-3-3 genes above, named TFT1-TFT12, via cDNA cloning and searches of the TIGR “Tomato Gene Index” EST database. By comparing the abundance of individual 14-3-3 gene transcripts in the various tissue-specific cDNA libraries that make up the  Tomato Gene Index, we found that there are significant differences in relative levels of 14-3-3 expression in different tissues. There were a total of 378 ESTs representing twelve 14-3-3 genes in the database that we searched (version 7.1), ranging from 2 to 63 ESTs per gene. Notably, ESTs from each gene exhibited a different distribution pattern within the database, indicating that none of the tomato 14-3-3s are co-regulated. Furthermore, different tissues displayed distinctive compositions of 14-3-3 isoforms. For example, the figure below shows the difference in composition of the pools of 14-3-3 transcripts in roots and fruits. Note especially  TFT7 and TFT9.
These genes are also differentially regulated following various stress treatments.

For example, this figure illustrates the increased expression of three 14-3-3 genes during a disease resistance response. The figure shows mRNA levels of TFT4, TFT6 and TFT1 at different times after elicitation of the response. The "events" diagram indicates the phases of the response characterised by the oxidative burst (OX), the synthesis of hormones such as ethylene and salicylic acid (C2H4 & SA), and the hypersensitive response (HR).
 

In a wound response, some genes are up-regulated, whilst others are repressed. Two examples are shown in this figure of mRNA levels in tissues harvested various times after wounding.


Tomato v. Tobacco
We are also interested in using tobacco as a system to examine some aspects of 14-3-3 biology.

Tomato and tobacco are closely related members of the Solanceae, and analysis of available 14-3-3 cDNA sequences from these two plants suggests that orthologous genes can be identified. This contrasts the situation for a similar comparison between tomato and Arabidopsis cDNAs, where pairs of orthologues cannot be identified. Below is a cladogram illustrating the relationships between the tomato 14-3-3 cDNAs (TFT genes) and tobacco cDNAs (isoform_A etc.) which we have collated from the sequence databases.
Whilst this analysis identifies a number of orthologous pairs, it also suggests that more 14-3-3 genes from each species are yet to be identified.


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