Background Plants change their surrounding soil microbiome by root exudates and these conditioned microbiomes impact the performance of the present as well as the next plant generation as for example in crop rotations. The big challenge is that such ‘microbiome feedbacks’ are highly context-dependent, i.e. they vary in strength and direction dependent on the local soil environment – of which the driving factor(s) remain unknown. Including maize in crop rotations involves benzoxazinoids (BXs), which are exuded from roots and alter the soil microbiome, which in turn affects growth and defence of the following crop. Results Here, we grew wild-type and BX-depleted maize in the field to differentially condition their soil microbiome and we found varying feedbacks on wheat performance dependent on the local physicochemical soil parameters. Using multivariate, correlation and modelling approaches and including additional data from two previous field experiments, we identified plant-available (PA) iron to be associated with BX-dependent microbiome feedbacks on wheat. The BX-conditioned soil microbiome caused wheat to grow taller at low levels of soil PA-iron but smaller at high levels. This finding was generalized by testing these maize microbiome feedbacks on the model plant Arabidopsis thaliana using soil batches containing different levels of iron. Consistent with wheat, a significant inverse relationship between soil PA-iron levels and plant growth was found. This relationship was experimentally validated with Arabidopsis thaliana grown at low levels of soil iron where iron supplementation abolished the beneficial feedback of the BX-conditioned soil microbiome. Conclusion Together, these findings revealed that beneficial microbiome feedbacks occur at low levels of plant-available iron, i.e. when plants grow in a suboptimal soil, but they are lost when plants are nutritionally well supported. These results underscore the importance of iron availability in soil for beneficial microbial feedbacks on plant growth and predict agronomic benefits of incorporating maize in crop rotations on low iron soils. <MediaObject ID="MOESM2"><VideoObject FileRef="MediaObjects/40168_2026_2493_MOESM2_ESM.mp4" VideoID="4-yt3PHhyDKE8F2J3K64ks"><Caption Language="En" xml:lang="en"><CaptionContent>Video Abstract</CaptionContent></Caption></VideoObject></MediaObject>

Soil iron modulates beneficial maize microbiome feedbacks in rotations with wheat

期刊论文
出版模式：

开放获取
发表日期：

2026年8月4日

查看全文

Jan Waelchli,
Henry Janse van Rensburg,
Katja Stengele,
Viola D’Adda,
Selma Cadot,
Veronica Caggìa,
Valentin Gfeller,
Klaus Schlaeppi

摘要

Background

Plants change their surrounding soil microbiome by root exudates and these conditioned microbiomes impact the performance of the present as well as the next plant generation as for example in crop rotations. The big challenge is that such ‘microbiome feedbacks’ are highly context-dependent, i.e. they vary in strength and direction dependent on the local soil environment – of which the driving factor(s) remain unknown. Including maize in crop rotations involves benzoxazinoids (BXs), which are exuded from roots and alter the soil microbiome, which in turn affects growth and defence of the following crop.

Results

Here, we grew wild-type and BX-depleted maize in the field to differentially condition their soil microbiome and we found varying feedbacks on wheat performance dependent on the local physicochemical soil parameters. Using multivariate, correlation and modelling approaches and including additional data from two previous field experiments, we identified plant-available (PA) iron to be associated with BX-dependent microbiome feedbacks on wheat. The BX-conditioned soil microbiome caused wheat to grow taller at low levels of soil PA-iron but smaller at high levels. This finding was generalized by testing these maize microbiome feedbacks on the model plant Arabidopsis thaliana using soil batches containing different levels of iron. Consistent with wheat, a significant inverse relationship between soil PA-iron levels and plant growth was found. This relationship was experimentally validated with Arabidopsis thaliana grown at low levels of soil iron where iron supplementation abolished the beneficial feedback of the BX-conditioned soil microbiome.

Conclusion

Together, these findings revealed that beneficial microbiome feedbacks occur at low levels of plant-available iron, i.e. when plants grow in a suboptimal soil, but they are lost when plants are nutritionally well supported. These results underscore the importance of iron availability in soil for beneficial microbial feedbacks on plant growth and predict agronomic benefits of incorporating maize in crop rotations on low iron soils.

Video Abstract