Fig. 6: Schematic hypothetical working model of ATG5- and ATG7-mediated autophagy in modulating male fertility in Arabidopsis.
From: Autophagy modulates Arabidopsis male gametophyte fertility and controls actin organization
In WT Arabidopsis, autophagy modulates sperm cell biogenesis and the directional growth of pollen tubes during fertilization. This is achieved by maintaining appropriate levels of actin depolymerization factors ADF7 and Profilin2 at appropriate levels through NBR1-mediated autophagic degradation. In the context of atg5 or atg7 mutants, compromised autophagy leads to an excessive accumulation of ADF7 and Profilin2 in pollen grains and tubes. This accumulation disrupts the spatiotemporal arrangement of actin filaments. As a result, it incites significant aberrations in spermatogenesis and directional pollen tube growth during the fertilization.
