I have RNA sequence data for six Zingiberaceae families. ( four from Zingiber officinale and two from kaempferia parviflora ). These samples are sequenced without any biological replicates and collected from different places.

My objectives are

1. To identify any differently expressed genes by comparing these samples.
2. Analyse gene function and pathway.
3. To identify key regulators/ genes involved in the biosynthesis of metabolites

Kindly suggest an approach to do this. Thanks