Proteomic Responses of the Springtail Folsomia candida to Drought

TL;DR

This study explores how springtails respond to drought at the protein level, finding that they reduce growth and reproduction but can survive until conditions improve.

Contribution

The study provides new insights into the proteomic responses of springtails to drought, revealing minimal stress-related protein changes but reduced growth-related proteins.

Findings

Drought-exposed springtails show reduced abundance of proteins related to growth and reproduction.

Proteomic analysis reveals minimal induction of cellular stress-handling proteins during drought.

Cytoskeleton-related pathways are down-regulated in drought conditions, correlating with reduced somatic growth.

Abstract

Springtails are small insect-like animals living in the soil almost all over the world. Most springtails are less than 5 mm in length, yet they can have great influence on the fertility of soil because they occur in very high numbers, sometimes in hundreds of thousands per square meter. These animals are adapted to life in moist soil and in many respects have a physiology resembling freshwater animals. Here, we explore the functional proteins in springtails when they are stressed by drought conditions. We find that proteins important for growth and reproduction are becoming less abundant in drought-exposed animals, but on the other hand, we see no strong indication of proteins related to cellular stress handling being more abundant. This suggests that springtails will stop growing and egg laying when they are experiencing drought but will be able to survive until soils become moist again.

Springtails are adapted to life in the pore space of soil, where humidity in moist soil is close to saturation. Drought is the most important limiting factor for springtails; however, their molecular and physiological adaptations to low humidity are not well understood. The present study explored the global proteomic drought response of the springtail, Folsomia candida (Isotomidae, Collembola). In relatively dry soil (−360 kPa), adult springtails initially lost body water but re-established the normal body water content over the following two weeks. Nano LC–MS/MS analysis identified a total of 1729 unique proteins. Proteomic analysis and pathway enrichment found that the proteome generally did not show a dramatic induction of proteins in response to drought stress. After an initial down-regulation of pathways related to metabolism and growth, these pathways gradually returned to the same levels as in moist soil. Other pathways such as the cytoskeleton pathway, which is important in cell proliferation and differentiation, were predominantly down-regulated throughout the experiment in drought-exposed animals, which correlated with essentially no somatic growth of the springtails in dry soil. This study facilitates the understanding of the consequences of climate change on soil functioning and fertility.

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