Comparative analysis of two sister Erythrophleum species (Leguminosae) reveal contrasting transcriptome-wide responses to early drought stress

Physiology and transcriptomics highlight the underlying mechanism of sunflower responses to drought stress and rehydration

Drought can adversely influence the crop growth and production. Accordingly, sunflowers have strong adaptability to drought; hence, we conducted analyses for sunflower seedlings with drought stress and rehydration drought acclimation through physiological measurements and transcriptomics. It showed that drought can cause the accumulation of ROS and enhance the activity of antioxidant enzymes and the content of osmolytes. After rehydration, the contents of ROS and MDA were significantly reduced concomitant with increased antioxidant activity and osmotic adjustment. Totally, 2,589 DEGs were identified among treatments. Functional enrichment analysis showed that DEGs were mainly involved in plant hormone signal transduction, MAPK signaling, and biosynthesis of secondary metabolites. Comparison between differentially spliced genes and DEGs indicated that bHLH025, NAC53, and SINAT3 may be pivotal genes involved in sunflower drought resistance. Our results not only highlight the underlying mechanism of drought stress and rehydration in sunflower but also provide a theoretical basis for crop genetic breeding.

Effect of seasonality on the population density of wetland aquatic insects: A case study of the Hawr Al Azim and Shadegan wetlands, Iran

Aim:

Wetlands are extremely suitable ecosystems to assess the effect of climate change on the density of aquatic insects. This study aimed to assess the effect of seasonality on populations of aquatic insects in the Hawr Al Azim and Shadegan wetlands.

Materials and Methods:

The insect samplings were conducted at a large area of the Hawr Al Azim and five different sites of the Shadegan wetlands. In total, 18,534 arthropods of different life stages, including 12 orders containing 51 families, were collected and identified from the selected sites of the Shadegan and Hawr Al Azim wetlands.

Results:

Results showed that the population density of wetland aquatic insects gradually increased as the average daily temperature decreased, positively increased with daily mean relative humidity and precipitation, and decreased with the mean daily evaporation between October and April. Conversely, the population density of wetland aquatic insects gradually decreased with increasing average daily temperature and reduction of the mean relative humidity and precipitation and increasing the average evaporation from April to September. When differences between the average daily and water temperatures reached minimum in April, the population density of wetland aquatic insects reached maximum and turned mainly to families that they have high level of biological indices, indicating that wetlands have clean waters around the spring. While around the autumn conversely, they mostly changed to families that they have low level of biological indices, indicating that wetlands have unclean waters.

Conclusion:

The present study showed an optimum condition for the growth of insects around spring. Seasonality affects the population density of wetland aquatic insects during a year.