Oogenesis is a fundamental process that forms the egg and, is crucial for the transmission of genetic information to the next generation. Drosophila oogenesis has been used extensively as a genetically tractable model to study organogenesis, niche-germline stem cell communication, and more recently reproductive aging including germline stem cell (GSC) aging. Autophagy, a lysosome-mediated degradation process, is implicated in gametogenesis and aging. However, there is a lack of genetic tools to study autophagy in the context of gametogenesis and GSC aging. Here we describe the generation of three transgenic lines mcherry-Atg8a, GFP-Ref(2)P and mito-roGFP2-Orp1 that are specifically expressed in the germline compartment including GSCs during Drosophila oogenesis. These transgenes are expressed from the nanos promoter and present a better alternative to UASp mediated overexpression of transgenes. These fluorescent reporters can be used to monitor and quantify autophagy, and the production of reactive oxygen species during oogenesis. These reporters provide a valuable tool that can be utilized in designing genetic screens to identify novel regulators of autophagy and redox homeostasis during oogenesis.

Autophagy is a conserved process that degrades cytoplasmic components and organelles in metazoan cells including germline stem cells. Although autophagy is implicated in the aging of stem cells, the precise mechanism are still unknown. Here we show that elevating autophagy by overexpressing (OE) Drosophila Autophagy-related gene 8a (Atg8a) in the female Germline stem cells (GSCs) delays their loss due to aging. However, sustained elevated autophagy levels in old flies promote GSC loss due to cell death. In contrast, knockdown of Atg8a (Atg8aRNAi) in GSCs accelerates their loss. Atg8aOE GSCs show elevated autophagy flux, and increased mitotic activity even at 8 weeks of age. Atg8aOE GSCs possess smaller-sized mitochondria and exhibit reduced mitochondrial oxidative stress in the GSCs. However, in contrast Atg8aRNAi GSCs have elevated mitochondrial ROS and possess larger mitochondria. Finally, our data show that Atg8aOE GSCs occupy the stem cell niche for longer duration with the aid of elevated E-cadherin at the GSC-cap cell contact sites. Our data suggests that elevated autophagy promotes GSC maintenance and activity, and delays their aging.