Wheat straw increases the defense response and resistance of watermelon monoculture to Fusarium wilt

Lili Tang,Siqi Wang,Fengzhi Wu,Shaorui Nie,Chao Fan,Wenhui Li,Kai Pan

doi:10.1186/s12870-019-2134-y

Abstract

BackgroundWheat straw is a rich resource worldwide. Straw return is an effective strategy to alleviate soil-borne diseases on monoculture watermelon. Previous studies focus on soil structure, physical and chemical properties; however, little is known about the molecular responses on host plant.ResultsNo significant difference on the population of Fusarium oxysporum f.sp. niveum race 1(Fon1) in rhizosphere soil was found between control (no addition of wheat straw) and the treated groups (addition of 1% (T1) or 2% (T2) wheat straw). RNA-Seq analysis showed that 3419 differentially expressed genes were clustered into 8 profiles. KEGG analysis revealed that phenylpropanoid biosynthesis and plant hormone signal transduction were involved in wheat straw induced response in monoculture watermelon. Genes in lignin biosynthesis were found to be upregulated, and the lignin and auxin contents were higher in T1 and T2 compared to the control. Lignin was also enriched and the Fon1 population decreased in watermelon roots treated with wheat straw. The enzyme activities of phenylalanine ammonia-lyase and peroxidase were increased.ConclusionsOur data suggest that the addition of wheat straw enhances the defense response to Fon1 infection in watermelon through increasing lignin and auxin biosynthesis.

Highlights

Wheat straw is a rich resource worldwide
The disease incidences in Addition of 1% wheat straw (T1) and Addition of 2% wheat straw (T2) were all significantly lower than in Without adding wheat straw (CK) at different time points, and that in T1 was significantly lower than in T2 and CK in the autumn of 2017 experiment
The root length was longer and plant height was taller in T1 and T2 than that in CK at each time point, while the root length and plant height in T1 and T2 were similar (Fig. 1c, d)

Summary

Introduction

Wheat straw is a rich resource worldwide. Straw return is an effective strategy to alleviate soil-borne diseases on monoculture watermelon. Long-term monoculture has led to widespread of Fusarium wilt [1], which is primarily caused by Fusarium oxysporum, a soil-borne fungus that causes approximately 30–50% watermelon yield losses worldwide [2]. Fusarium wilt has previously been controlled mainly by soil fumigation [3], fungicides [4], and the use of resistant cultivars [5]. These control measures are not desirable and can directly increase environmental pollution. Biological control, which uses natural antagonists, Crop straw is used extensively in modern agriculture worldwide and is the oldest and most economical management practice to relieve monoculture problems and increase crop yields and quality. Previous studies showed that root and stem rot of cucumber could be controlled by lettuce incorporation into the soil; grape residue and garlic straw were proven inhibiting Fusarium wilt and root-knot nematodes in tomato, respectively [8,9,10]

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Conclusion