No abstract

Zea mays (maize) makes phytoalexins such as sesquiterpenoid zealexins, to combat invading pathogens. Zealexins are produced from farnesyl diphosphate in microgram per gram fresh weight quantities. As farnesyl diphosphate is also a precursor for many compounds essential for plant growth, the question arises as to how Z. mays produces high levels of zealexins without negatively affecting vital plant systems. To examine if specific pools of farnesyl diphosphate are made for zealexin synthesis we made CRISPR/Cas9 knockouts of each of the three farnesyl diphosphate synthases (FPS) in Z. mays and examined the resultant impacts on different farnesyl diphosphate-derived metabolites. We found that FPS3 (GRMZM2G098569) produced most of the farnesyl diphosphate for zealexins, while FPS1 (GRMZM2G168681) made most of the farnesyl diphosphate for the vital respiratory co-factor ubiquinone. Indeed, fps1 mutants had strong developmental phenotypes such as reduced stature and development of chlorosis. The replication and evolution of the fps gene family in Z. mays enabled it to produce dedicated FPSs for developmentally related ubiquinone production (FPS1) or defense-related zealexin production (FPS3). This partitioning of farnesyl diphosphate production between growth and defense could contribute to the ability of Z. mays to produce high levels of phytoalexins without negatively impacting its growth.

No abstract

BackgroundDepression and anxiety affect 4% to 14% of Australians every year; symptoms may have been exacerbated during the COVID-19 pandemic. We examined recent patterns of antidepressant use in Australia in the period 2015 to 2021, which includes the first year of the pandemic.MethodsWe used national dispensing claims for people aged ≥10 years to investigate annual trends in prevalent and new antidepressant use (no antidepressants dispensed in the year prior). We conducted stratified analyses by sex, age group and antidepressant class. We report outcomes from 2015 to 2019 and used time series analysis to quantify changes during the first year of the COVID-19 pandemic (March 2020 to February 2021).ResultsIn 2019 the annual prevalence of antidepressant use was 170.4 per 1,000 women and 101.8 per 1,000 men, an increase of 7.0% and 9.2% from 2015, respectively. New antidepressant use also increased for both sexes (3.0% for women and 4.9% for men) and across most age groups, particularly among adolescents (aged 10-17 years; 46%-57%). During the first year of the COVID-19 pandemic, we observed higher than expected prevalent use (+2.2%, 95%CI 0.3%, 4.2%) among females, corresponding to a predicted excess of 45,217 (95%CI 5,819, 84,614) females dispensed antidepressants. The largest increases during the first year of the pandemic occurred among female adolescents for both prevalent (+11.7%, 95%CI 4.1%, 20.5%) and new antidepressant use (+15.6%, 95%CI 8.5%, 23.7%).ConclusionAntidepressant use continues to increase in Australia overall and especially among young people. We found a differential impact of the COVID-19 pandemic in treated depression and anxiety, greater among females than males, and greater among young females than other age groups, suggesting an increased mental health burden in populations already on a trajectory of increased use of antidepressants prior to the pandemic. Reasons for these differences require further investigation.