Peanut genotypic stress tolerance imprints the rhizobacterial community patterns in acidic soil: Evidence from two years of field trials

Abstract

Context or problem

Developing stress-tolerant plants continues to be the goal of breeders due to their realized yields and stability. The rhizosphere microbiome is a central determinant of plant tolerance to soil environmental stress, but the association between genotypic differences in peanut (Arachis hypogaea L.) stress tolerance and rhizobacterial community patterns remains unclear in acidic soils.

Objective or research question

We aim to screen the acid soil-tolerant peanut varieties and explore the relationship between rhizobacterial community patterns and peanut acid soil tolerance.

Methods

A two-year field trial was conducted during 2022–2023. In 2022, We grew 27 peanut varieties in two experimental fields with different initial soil pHs (4.70 and 5.58), and screened four acidic soil-tolerant and 4 acidic soil-sensitive peanut varieties. In 2023, we replanted the screened eight peanut varieties in the pH 4.70 field. Bulk and rhizosphere soil samples were collected to analyze the soil chemical properties and bacterial community patterns of different genotypic peanuts.

Results

The four acidic soil-tolerant peanuts had lower exchangeable aluminum content and higher pH and exchangeable calcium contents in the rhizosphere soils in the pH 4.70 field relative to the acid soil-sensitive peanuts. These differences in the rhizosphere chemical properties further caused distinct rhizosphere bacterial communities of acid soil-tolerant peanuts from acid soil-sensitive peanuts. The acid soil-tolerant peanuts had much higher relative abundance of ASVs (Amplicon Sequence Variants) related to carbon and nitrogen transformation, while the acid soil-sensitive peanuts formed a more complex co-occurrence network by exacerbating the competition between ASVs. Further, the acid soil-tolerant peanuts harbored a higher relative abundance of positive keystone (Sphingomona) and a lower relative abundance of negative keystone (IMCC26256, Elsterales, and WPS_2) than the acid soil-sensitive peanuts. These differences between the acid soil-tolerant and acid soil-sensitive peanuts were observed only in the rhizosphere soils of the pH 4.70 field but not in the bulk soils or the pH 5.58 field.

Conclusion

Peanut genotypic stress tolerance imprints the rhizobacterial community and association network patterns.

Implications or significance

Our findings provided resistant cultivar resources for peanut cultivation and breeding in acidic soils and highlighted the rhizobacterial community and association network patterns as indicators of genotypic peanut stress tolerance in acid soil.