The objective of this work was to evaluate the effects of infestation by Meloidogyne javanica on the vegetative development, nutritional characteristics, and antioxidant potential of beet (Beta vulgaris). Inoculation in beet seedlings was performed with 0, 1,000, 2,500, 5,000, and 10,000 eggs and with possible second-stage juveniles (J2) of nematodes. Plants were collected 60 days after inoculation for the evaluation of the nematological and vegetative parameters, the physicochemical composition, and the content and activity of antioxidant compounds. The population levels of M. javanica reduced the mass and diameter of the tuber, comparing inoculum levels of 0 and 10,000 eggs + J2 of nematodes. There was a significant difference for the number of galls and nematodes per root system, with a proportional increase of population density according to the inoculation level. The reproduction factor in all infected treatments was above 1. Although the infection by M. javanica reduced the plant protein content, other compounds, such as betalains, sugars, and phenolics, were not affected. The inoculation by M. javanica negatively affects tuber development, but does not alter the antioxidant potential of beet.

Root-knot nematode infection has a direct and negative impact on the commercial value of beet (Beta vulgaris L.) tubers. The aim of this study was to evaluate induced resistance in beet tuberous roots infected with different population levels of Meloidogyne javanica (Treub, 1885) Chitwood, 1949. Plants were inoculated with increasing inoculum levels (0, 1500, 5000, and 10 000 eggs + juveniles [J2]) and treated with different products that can potentially induce resistance: mannanoligosaccharides (MOS), citrus biomass, and acibenzolar-S-methyl (ASM). Vegetative, nematological, and enzymatic parameters were evaluated after 60 d. In general, when compared to the control (water), inducers did not promote a positive effect on tuber diameter and weight, regardless of the inoculum level. Only the weight of plants inoculated with 5000 eggs + J2 and treated with citrus biomass (40.70 g) increased compared with the control (32.38 g). The treatments did not reduce the number of galls, nematodes per root system, and nematodes per gram of root. Resistance inducers increased catalase activity (CAT) and phenylalanine ammonia-lyase (PAL) and MOS and ASM were the most effective. The highest CAT activity was for ASM and 5000 eggs + J2, resulting in 42.44% compared with the control. The MOS and ASM exhibited the highest PAL activity (0.22 and 0.15 mg trans-amino acid h-1 mg-1 protein, respectively) compared with the control (0.03 mg trans-amino acid h-1 mg-1 protein) in uninoculated plants. Results led us to conclude that inducers should not be used in isolation to control nematodes in beet. However, deformed tubers can be used in manufacturing, thus preventing food waste. In addition, new rates and application intervals should be evaluated to help control nematodes in beet plants.

Pratylenchus zeae Graham is one of the most important nematode species found in sugarcane and has been reported in the main sugarcane-producing regions of Brazil, especially in areas of commercial production in the state

Background The root-knot nematode Meloidogyne javanica can infect beetroots, causing extensive damage to this food crop. As chemical and genetic control tactics have shown limited efficacy, new strategies are needed to improve the integrated management of this parasite. This study assessed the influence of potential defence elicitors and M. javanica infection on the mineral composition of beetroot. Plants were treated with acibenzolar-S-methyl (ASM), citrus biomass, or a mannanoligosaccharide-based product (MOS) and inoculated with 1000 eggs and second-stage juveniles of M. javanica. At 60 days after inoculation, beetroot plants were harvested and evaluated for nematode population density, vegetative growth, and mineral content. Results All potential elicitors reduced nematode population density in beetroots (p ≤ 0.10) and improved the vegetative parameters of inoculated plants (p ≤ 0.05), except shoot fresh weight. Some minerals were found to be negatively affected by treatments, particularly calcium, whose levels were consistently lower in treated plants. On the other hand, M. javanica inoculation increased magnesium, iron, manganese, zinc, and copper contents in beetroots. However, the latter mineral (Cu content) of inoculated plants was positively influenced by MOS and ASM. Conclusion Potential elicitor treatments did not improve the mineral composition of beetroot, but were effective in reducing nematode population density. Plants inoculated with M. javanica had higher mineral levels. However, gall formation decreases the commercial value of the crop and might render it unsuitable for commercialisation. M. javanica-infected beetroots may be used for nutrient extraction or sold to food processing industries.

Beetroot is rich in nutrients and bioactive compounds, such as, betalains and phenolics. The objective of this work was to analyze the chemical composition and antioxidant properties of beetroot parasitized by Meloidogyne javanica and treated with elicitors. Beet seedlings were inoculated with 1000 eggs and second-stage juveniles of M. javanica and treated with elicitors based on mannan oligosaccharides, citrus biomass, or acibenzolar-S-methyl (ASM). At 60 days after inoculation, plants were evaluated for nematode reproduction factor (RF), proximate composition, betalains, phenolic compounds, and antioxidant activity. Beetroot was found to be susceptible to M. javanica, with RF values ranging from 15.26 to 27.94. ASM and citrus biomass treatments increased ash content by 15–25% in nematode-inoculated plants. There was no treatment effect on moisture or protein content, but uninoculated plants had higher total phenolic content (~35%) than inoculated plants. Nematode infection was found to compromise betalain production but did not impact antioxidant activity. Nematode-inoculated plants showed reduced sucrose content and increased glucose and fructose levels in all treatments. Regardless of the elicitor used, beetroots inoculated M. javanica exhibit deformities that render them unmarketable in fresh form. However, the results indicate that nematode-infected beetroot may be suitable for industrial processing and compound extraction.

Meloidogyne javanica is a plant-parasitic nematode that infects a wide range of vegetables. Its negative effects on crop yield and value are well documented. However, few studies have investigated the impact of the parasite on the nutritional value of vegetables. This study aimed to assess the effect of M. javanica parasitism on the vegetative characteristics, nematological parameters, chemistry composition and antioxidant activity of carrots. Seedlings were inoculated with 0 (control), 1000, 2500, or 5000 eggs and eventual second-stage juveniles (J2) of M. javanica. At 60 days after inoculation, plants were harvested and evaluated. Plants inoculated with 2500 eggs and J2 of M. javanica had higher root and tuber fresh weight than the control. Gall number increased with increasing inoculum density. The number of nematodes in the roots increased until 3000 specimens, decreasing thereafter. Proximate analysis revealed that plants inoculated with 1000 eggs and J2 of M. javanica or more had higher protein content in roots. In contrast, inoculation with 1775 nematodes or more resulted in a decrease in carotenoid content. There was no effect of inoculation on total phenolic content or antioxidant activity. Although, M. javanica infection did not have a marked impact on the nutritional quality of carrots, gall formation resulted in deformed roots of low commercial value.

Crambe is an oilseed, which pressing for oil extraction results in the waste called crambe cake. The aforementioned waste may present potential to control nematodes, since it derives from brassica species. The aim of the current study is to assess the best crambe cake application to control Meloidogyne javanica in lettuce plants. Five experiments were carried out in a greenhouse by adopting different crambe cake application procedures; each experiment comprised five treatments (0 (control), 5; 10; 15; 20 g crambe cake per 1 L soil). Lettuce seedlings were cultivated in soil treated with crambe cake, and inoculated with 5,000 nematode eggs and occasional juveniles (J2). Nematological and vegetative parameters were assessed 45 days after inoculation. Nematode reduction was observed in the experiment that applied doses close to 15 g crambe cake to the soil surface; nematode control recorded 83 and 68% for eggs and J2 total and per root gram, respectively. The same parameters showed up to 82 and 93% reduction when the cake was incorporated to the first 8 cm deep into the soil. The number of eggs and J2 per root system reduced by 93% when the cake was incorporated to the total soil volume. Overall, the crambe cake did not increase plant development; in some cases, phytotoxicity was observed at the highest doses.