# Mining of Potential Gene Resources for Breeding Nutritionally Improved Maize
## 6 Identification of Maize Potential Gene Resources for Mineral Content Improvement
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Genes** & **Protein Function** & **Maize Orthologs** & **Gene ID** & **Strategy** & **References** \\ \hline \multirow{8}{*}{_NAS_} & & _NAS1_ & _Zm00001 eb396230_ & \multirow{8}{*}{overexpression} \\  & & _NAS2_ & _Zm00001 eb014700_ & \multirow{8}{*}{overexpression} \\  & & _NAS3_ & _Zm00001 eb052890_ & \multirow{8}{*}{} \\  & & _NAS4_ & _Zm00001 eb218440_ & \\  & & _NAS56_ & _Zm00001 eb36110_ & \\  & & _NAS8_ & _Zm00001 eb396250_ & \\  & & _NAS9_ & _Zm00001 eb14680_ & \\  & & _NAS10_ & _Zm00001 eb396280_ & \\ \hline \multirow{2}{*}{_NAAT_} & \multirow{2}{*}{nicotianaamine aminotransferase} & _NAAT1_ & _Zm00001 eb203230_ & \multirow{2}{*}{} \\  & & _PCO115235C_ & _Zm00001 eb240650_ & \\ \hline _NRAMP1_ & carrier protein & _NRAT1_ & _Zm00001 eb224770_ & \multirow{2}{*}{overexpression} & [120] \\ \hline _NRAMP5_ & carrier protein & _NRAT5_ & _Zm00001 eb304610_ & \multirow{2}{*}{overexpression} & [121] \\ \hline _FRD3_ & carrier protein & _MATE1_ & _Zm00001 eb143800_ & \multirow{2}{*}{overexpression} & [122] \\  & & _Zm00001 eb424530_ & & \\ \hline _FRD1_ & carrier protein & _MATE3_ & _Zm00001 eb008790_ & \multirow{2}{*}{overexpression} & [123] \\ \hline _VIT1_ & carrier protein & & _Zm00001 eb424350_ & \multirow{2}{*}{knockout} & [100] \\  & & _Zm00001 eb099160_ & & \\  & & _Zm00001 eb312010_ & & \\ \hline _NRAMP3_ & carrier protein & _NRAT3_ & _Zm00001 eb400560_ & \multirow{2}{*}{} \\  & & _NRAT4_ & _Zm00001 eb030050_ & \\  & & _Zm00001 eb051790_ & & \\ \hline _FER_ & storage protein & _FER1_ & _Zm00001 eb195010_ & \multirow{2}{*}{} \\  & & _FER2_ & _Zm00001 eb404870_ & \\ \hline _IRO2_ & transcription factor & _BHLH54_ & _Zm00001 eb362800_ & \multirow{2}{*}{} \\  & & _BHLH126_ & _Zm00001 eb140680_ & \\ \hline _BHLH58_ & transcription factor & _BHLH118_ & _Zm00001 eb289490_ & \multirow{2}{*}{} \\ \hline _BHLH59_ & transcription factor & _BHLH128_ & _Zm00001 eb209480_ & \\  & & _BHLH129_ & _Zm00001 eb229950_ & \\ \hline _BHLH29_ & transcription factor & _BHLH100_ & _Zm00001 eb420910_ & \multirow{2}{*}{} \\  & & _BHLH101_ & _Zm00001 eb085690_ & \\ \hline _BHLH300_ & transcription factor & _BHLH54_ & _Zm00001 eb362800_ & \multirow{2}{*}{} \\ \hline _IDEF1_ & transcription factor & _AB147_ & _Zm00001 eb198710_ & \\  & & _AB149_ & _Zm00001 eb259870_ & \\ \hline _CSN6_ & coactivator & _SI605023C06B_ & _Zm00001 eb199540_ & \\  & & _Zm00001 eb034040_ & \\ \hline _RAB6A_ & small GTPase & _IDP871_ & _Zm00001 eb006940_ & \multirow{2}{*}{} \\ \hline _HRZ_ & Fe-binding ubiquitin ligase & _541975_ & _Zm00001 eb360580_ & \\  & & _Zm00001 eb156300_ & \\  & & _Zm00001 eb294920_ & \\ \hline _MTP1_ & carrier protein & _UMC2311_ & _Zm00001 eb385520_ & \\  & & _Zm00001 eb420140_ & \\  & & _Zm00001 eb354910_ & \\ \hline \end{tabular}
\end{table} 
Table 5: List of potential gene resources for enhancing mineral contents in maize. Identification of Maize Potential Gene Resources for Other Secondary Metabolites Content Improvement  
In addition to vitamins, there are many secondary metabolites in plants, mainly phenolic compounds. The majority of the phenolic compounds in maize are phenolic acids, such as ferulic, vanillalic, caffeic, syringic, synaptic and \(\varrho\)-coumaric acids, and polyphenols, including lignins and lignans [131]. Phenolic compounds are essential for plant growth and development and are considered as defensive barriers of plants. However, the detailed mechanism is still unknown, and it is speculated that it plays an antioxidant role [132]. Anthocyanins are flavonoids that confer plant seeds and fruits various colors, from red to purple. They are not just protective agents for plants. Anthocyanins are also used as supplements in health care products to control obesity and diabetes and improve vision and brain function [1]. Many genes related to anthocyanin synthesis have been identified and applied in genetic engineering to improve anthocyanin content in maize. These include many transcription factors that regulate anthocyanin synthesis.