Identification Of Melon IQD Gene Family And Preliminary Study On The Functions Of CmIQD1 And CmIQD31

Melon is a widely cultivated dicotyledonous horticultural crop in the world.Its fruit has rich nutritional and medicinal value.In this study,Cucumis melo L.cv Hetao melon was used as the research material to identify the melon IQ67 domain（IQD）gene family,and two IQD gene family genes CmIQD1（MELO3C025505）and CmIQD31（MELO3C002201）were selected for research.The main results are as follows:（1）Take the members of arabidopsis IQD gene family as a reference,29 melon IQD genes were screened and identified,the encoded proteins can be divided into four subfamilies by phylogenetic tree analysis;Melon IQD gene family has 19homologous genes with tomato and cucumber.（2）Subcellular experiments showed that the proteins expressed by melon genes CmIQD1 and CmIQD31 were located in the cell membrane.Yeast two hybrid experiment showed that CmIQD1 and CmIQD31 had no self activation,and CmIQD31 interacted with Cm CML13.（3）The overexpression vectors and gene editing vectors of CmIQD1 and CmIQD31 genes were constructed,and a total of 69 imported melon fruits were obtained by pollen-tube pathway.The average positive rates of the four recombinant vector p CAMBIA-IQD1,p CAMBIA-IQD31,p HSE401-IQD1,p HSE401-IQD31 T₁seeds were:3.3%,3.6%,2.6%,3.1%respectively.Through T₁ screening and T₂generation-adding,the fruit weight,fruit vertical and horizontal diameter and other data of T₃ transgenic homozygous lines were obtained and counted.（4）After testing and statistics,the average fruit shape index of CmIQD1overexpressing three lines CmIQD1-Oe1,CmIQD1-Oe2,CmIQD1-Oe3 is 1.17,which is significantly higher than the average fruit shape index of control fruit 1.09;The average fruit weight of CmIQD31 three lines CmIQD31-Oe1,CmIQD31-Oe2,and CmIQD31-Oe3 is 1308.4 g,which is significantly heavier than the average fruit weight of the control fruit 1149.4 g.（5）Statistics showed that The average length of leaves of the three plant lines overexpressing CmIQD1 was 5.2 cm,which was significantly shorter than the average length of control leaves by 6.2 cm.The average width of leaves of the three plat lines overexpressing CmIQD1 was 7.9 cm,which was significantly wider than the average width of control leaves of 7.0 cm;the average length of CmIQD31overexpressed three plant lines was 6.3 cm and the average length of control leaves was 6.2 cm,there was no significant change.And the average width of leaves was 8.1cm,significantly wider than the average width of the control leaves by 7.0 cm.To sum up,overexpression the gene CmIQD1 resulted in an increase in fruit shape index,a decrease in leaf length,and an increase in leaf width in melon fruit,but no significant effect on fruit weight;Overexpression the gene CmIQD31 resulted in increased fruit weight and leaf width,but had no significant effect on leaf length and fruit shape index.