Microbial mechanism of zinc fertilizer input on rice grain yield and zinc content of polished rice

Abstract

Zinc is an essential minor element for rice growth and human health, which can also change the structure of the microorganisms. However, it remains unclear for the effects of zinc fertilizer on microbiome function in agricultural soils and crops. To solve this research gap, we investigated the relationship between improving rice (Oryza sativa L.) yield, Zn concentration, soil microbial community diversity, and function by the application of Zn fertilizer. The field trials included three rice varieties (Huanghuazhan, Nanjing9108, and Nuodao-9925) and two soil Zn levels (0 and 30 kg ha–1) in Jiangsu province, China. As a test, we studied the variety of soil bacterial composition, diversity, and function using 16S rRNA gene sequencing. The results showed that soil Zn application reduced the diversity of microbial community, but the bacterial network was more closely linked, and the metabolic function of bacterial community was improved, which increased the grain yield (17.34–19.52%) and enriched the Zn content of polished rice (1.40–20.05%). Specifically, redundancy analysis (RDA) and Mantel’s test results revealed soil total nitrogen (TN) was the primary driver that led to a community shift in the rice rhizosphere bacterial community, and soil organic carbon (SOC) was considered to have a strong influence on dominant phyla. Furthermore, network analysis indicated the most critical bacterial taxa were identified as Actinobacteria, Bacteroidetes, Proteobacteria, and Chloroflexi based on their topological roles of microorganisms. KEGG metabolic pathway prediction demonstrated that soil Zn application significantly (p < 0.05) improved lipid metabolism, amino acid metabolism, carbohydrate metabolism, and xenobiotic biodegradation. Overall, their positive effects were different among rice varieties, of which Nanjing-9108 (NJ9108) performed better. This study opens new avenues to deeply understand the plant and soil–microbe interactions by the application of fertilizer and further navigates the development of Zn-rich rice cultivation strategies.

Metallic micronutrients are associated with the structure and function of the soil microbiome

“…Previous studies have reported that micronutrients explained a large variation in the structure of microbial communities in agricultural soils receiving specific micronutrients 20 , while we further confirm the relationship between micronutrients and microbial structure in a wider range of soils with more contrasting properties and under different land uses. Our finding is also consistent with some experiments showing that iron minerals shaped soil microbial community 21 and Zn fertilization decreased soil microbial diversity and altered community composition in paddy soil 22 . In general, soil pH is previously reported to be positively linked to soil bacterial diversity 4 , 23 and also negatively linked to micronutrient availability 24 .…”

Biomimetic Mineralization for Smart Biostimulant Delivery and Crop Micronutrients Fortification

“…We hypothesized that the Zn ions in the framework are contributing to the enhanced performance that we observed with plain ZIFs. This is consistent with the previous research showing the yield-promoting impacts of nanoscale metal and micronutrient treatments in other crops. , In addition, zinc fertilizers have been recently shown to alter the microbial communities in the rhizosphere, which promotes plant growth and eventually increases yield …”

The potential of irradiated inoculants consortium for zinc accumulation in rice mutant lines

“…Bio-fertilizer such as Rhizobacter, Azopirillum, and Bacillus sp are Zn-solubilizing bacteria that can enhance the content of Zn under a watered condition and significantly improve crop growth, yield, and Zn content. The varied Zn content in rice mutant lines by treatments was also previously reported [13]. The Zn content in grain is largely determined by genotype rather than by Zn fertilizer, which could be attributed to differences in Zn uptake behavior.…”

“…Soil microbes metabolize recalcitrant forms of soilborne nutrients to liberate these elements for plant nutrition [11]. Most nutrients are bound to organic molecules and are therefore minimally available for soil microbes such as bacteria and fungi, which possess the metabolic machinery to depolymerize and mineralize organic compounds [12,13]. The contents of these microbial cells are subsequently released, either through turnover or cell lysis.…”