초록
<P><B>Abstract</B></P> <P>Color change due to lycopene accumulation and decreasing β-xanthophyll and chlorophyll concentrations occurs during ripening of tomatoes (<I>Solanum lycopersicum</I>). The functions of the transcription factors <I>SNAC4</I> (<I>SlNAC48</I>, Accession number: NM 001,279,348.2) and <I>SNAC9</I> (<I>SlNAC19</I>, Accession number: XM 004,236,996.2) during ripening have been studied using virus-induced gene silencing (VIGS) to obtain <I>SNAC</I>s-silenced fruit. Silencing of <I>SNACs</I> led to delayed ripening associated with reduced ethylene production, lycopene accumulation, and yellow or orange fruit. Genes involved in carotenoid pathway flux and ethylene biosynthesis were consistently down-regulated. Silencing of <I>SNAC4</I>/9 altered tomato ripening processing. In <I>SNAC4</I>-silenced fruit, softening-related factors were down-regulated and there was less ABA (abscisic acid) than the negative control, whereas <I>SNAC9</I>-slilenced fruit showed an opposite phenotype. Exogenous ABA accelerated softening of <I>SNAC4</I>-silenced fruit, while exogenous nordihydroguaiaretic acid (NDGA) slowed down the softening of <I>SNAC9</I>-silenced fruit. Our results suggest that pathways dependent on ethylene and ABA are regulated by <I>SNAC4</I> and <I>SNAC9,</I> respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SNAC4/9-silenced fruits delayed the onset of ripening compared to negative control. </LI> <LI> Ethylene and pigment were lower in SNACs-silenced lines, related genes was down-regulated. </LI> <LI> SNAC4/9-silenced fruits had opposite patterns of firmness and abscisic acid. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>NAC effects tomato carotenoids biosynthesis and softing.</P> <P>[DISPLAY OMISSION]</P>