Identification And Analysis Of Hydroxypyruvate Reductase In Dianthus Chinensis

Hydroxypyruvate Reductase(HPR)is a key enzyme in the photorespiration pathway.Its product,glyceric acid,is entered into the chloroplast and catalyzed to the produce 3-PGA,which is used as the substrate in the Calvin cycle.From the transcriptome sequencing data of Dianthus chinensis,we obtained a gene annotated as HPR,Dch HPR1(ON229038).Its function was identified by TRV-mediated VIGS.And then,the gene expression profile,enzyme activity,anthocyanin content,reducing sugar content and ATP content were analyzed.The main results were as follows:1.The size of the gene is 1632 bp,which includes an open reading frame of 759 bp,and encodes 252 amino acids.Its deduced amino acid sequence is 71.26% similar to HPR sequences in other seven plants.2.The vector of p TRV2/Dch HPR1 was constructed.After infiltration of detached flower buds of Dianthus chinensis with Agrobacterium tumefaciens containing the recombinant plasmid,the color became lighter in the whole petals,especiallly in the center.Compared with the counterparts of the control,the expression of Dch HPR1 in the center decreased by 25.73%,and the enzyme activity was 0.45 times.At the same time,the contents of anthocyanin,reducing sugar and ATP significantly dropped.The expression of Dch HPR1 in the outsider decreased by 4.81%,and the enzyme activity was 0.86 times.Meanwhile,the contents of anthocyanin,reducing sugar and ATP significantly decreased.It indicates that the gene is related to the flower color of Dianthus chinensis.3.With the development of flower buds of Dianthus chinensis,the expression of Dch HPR1 increased slightly,but the enzyme activity,anthocyanin content,reducing sugar content and ATP content significantly increased.4.Among the three kinds of flower colors of Dianthus chinensis,the expression level of Dch HPR1 in flowers of white with purple center and of purple were 0.68 times and 1.37 times as much as that in the white flower,respectively.The enzyme activity,anthocyanin content,reducing sugar content and ATP content were the highest in the purple flower,which were significantly higher than those in the white flower.5.In different organs of Dianthus chinensis,the Dch HPR1 expression,enzyme activity and ATP content in the leaves were the highest and significantly higher than those in flowers.The anthocyanin content and reducing sugar content in flowers were the highest and significantly higher than those in the leaves.To sum up,Dch HPR1 is related to the flower color of Dianthus chinensis.Inhibiting its expression will lead the decreases of the contents of anthocyanin,reducing sugar and ATP.