Weeds in Cereal Crop Rotations May Host Fusarium Species That Cause Fusarium Head Blight and Grain Weight Losses in Wheat

Abstract

Fusarium Head Blight (FHB) is one of the most common worldwide wheat and other small grain diseases. The infection is caused by Fusarium graminearum and other related species, which significantly reduce grain yield and contaminate grains with mycotoxins which are harmful for humans and animals. Fusarium pathogen survives the winter well in plant debris left on the field. Weeds around and within crops are alternative hosts of Fusarium fungi when an economically important host plant is not present. This article focuses on the determination of DNA content of Fusarium species (F. graminearum and F. avenaceum) in artificially inoculated wheat plants with isolates from weeds, as well as its influence on the severity of FHB and spring wheat 1000-grain weight under field conditions. Fungal DNA content in grains was evaluated by quantitative real-time PCR. The results showed that the DNA concentration of F. graminearum was significantly higher in the grain than F. avenaceum. The severity of FHB when wheat heads were inoculated with F. graminearum was significantly higher than with F. avenaceum. All F. graminearum strains statistically significantly reduced the weight of spring wheat grains, while F. avenaceum did not affect the weight of 1000 grain. This investigation has shown that weeds in crop rotations are a potential source of FHB infection. However, the severity of the disease is more affected by the Fusarium species than the host plant. This experiment is, to our knowledge, the first report on the estimation of Fusarium DNA content in artificially inoculated wheat plants with isolates from weeds, as well as its comparison with pathogenicity to wheat and its effect on 1000-grain weight.

Diversity of Mycotoxins Produced by Fusarium Strains Infecting Weeds

“…This study compared the mycotoxin contamination potential among various Fusarium species obtained from different host plant groups, including weeds and Triticum . Previous data have indicated that Fusarium isolates from various host plants can produce FHB disease with differing severity [ 27 , 28 ]. Weeds often become a source of pathogens when there are no significant host plants nearby [ 29 ].…”

“…An inoculation procedure was conducted on heads of the spring wheat cultivar ‘KWS Chamsin’ in 2019 at the Lithuanian Research Centre for Agriculture and Forestry in experimental fields. During mid-flowering, the main Fusarium pathogens responsible for Fusarium head blight (FHB), including F. avenaceum and F. graminearum , were isolated from the internal tissues of asymptomatic weeds and were used to inoculate the ears of spring wheat [ 28 ].…”

“…The study scheme is presented in Table 2 . The wheat head inoculation procedure was carried out following the methodology described in prior research studies [ 28 , 41 ].…”

“…The year 2019 had high humidity and warm temperatures during the wheat flowering and seed filling stages, which led to an elevated risk of Fusarium head blight (FHB) and subsequent mycotoxin production in harvested grains. More detailed information on meteorological conditions is available in the study by Matelionienė et al [ 28 ].…”

In Vitro Sensitivity Test of Fusarium Species from Weeds and Non-Gramineous Plants to Triazole Fungicides

“…Since triazole fungicides have been used for controlling different pathogens on crops for long periods, some Fusarium species showed tolerance to these chemicals [ 24 ]. Despite this, it is not clear how Fusarium strains isolated from alternative plants (weeds), which, in our previous studies, showed the ability to cause very intense FHB disease [ 6 ] produce mycotoxins [ 25 ] and reduce grain yield [ 26 ], respond to fungicides. Finally, it is valuable to monitor the sensitivity of Fusarium populations from different sources to fungicides as part of integrated disease and weed management to implement control strategies.…”