Identification of Weed-Suppressive Tomato Cultivars for Weed Management

The present study aims to identify tomato (Solanum lycopersicum L.) cultivars with weed-suppressive ability against target weed species in the tomato growing season. A greenhouse study was conducted with 17 tomato cultivars and target weeds Palmer amaranth (Amaranthus palmeri S. Wats), yellow nutsedge (Cyperus esculentus L.), and large crabgrass (Digitaria sanguinalis L.). Tomato plants and weed species were grown in the same pot. The height, chlorophyll, and dry weight biomass of the weeds were measured 28 days after sowing. The largest effect of tomato interference was on Palmer amaranth. Cultivar 15 reduced Palmer amaranth height, chlorophyll, and biomass by 58, 28, and 83%, respectively. Chlorophyll percentage of yellow nutsedge seedlings was suppressed by 15% by cultivar 64, whereas 13% of its height was reduced by cultivar 20. Cultivar 15 reduced biomass of yellow nutsedge by 40%. The percentage of chlorophyll of large crabgrass was reduced by 22% with cultivar 5, whereas the height and biomass were reduced by 35 and 44% with cultivars 38 and 63, respectively. Factoring all parameters evaluated, cultivars 38, 33, and 7 were most suppressive against the problematic weed species in tomato.

Invasion, distribution and habitat affiliation of Cyperus esculentus, a new weed in Slovenia

Cyperus esculentus (yellow nutsedge) is an alien species that started to spread in arable fields in Slovenia and has already become a noxious weed. In this study we present the spatio-temporal pattern of this invasion in Slovenia. Species was first recorded in 1980 and currently two hotspots are evident (Ljubljana Basin and Posočje). Habitat preferences of Cyperus esculentus and the floristic compostion of invaded plant communities were studied. These communites were compared to similar communities in Slovenia and to so far described vegetation types with dominating Cyperus esculentus in Europe. Based on these analyses we described new weed association, namely Digitario sanguinalis-Cyperetum esculenti.

Strategies for increased yellow nutsedge (Cyperus esculentus) control in turfgrass with halosulfuron, sulfentrazone and physical removal

Yellow nutsedge is one of the most widely distributed and troublesome weeds in the world. Field and greenhouse studies were conducted to optimize strategies for increased yellow nutsedge control in turfgrass with halosulfuron and sulfentrazone. In the field study in yellow nutsedge and perennial ryegrass mixture, single or sequential applications (three weeks after initial) of halosulfuron or sulfentrazone were made on June 3, June 23, July 15, or August 5 in 2013, 2014, 2015, and 2016. Percent yellow nutsedge control was rated within the same growing season on Sept 17 and the following year on June 3 for carry-over control. Field and greenhouse studies confirm that sequential applications of halosulfuron with a three-week interval resulted in > 95% control in a yellow nutsedge/turfgrass mixture. In a greenhouse study, both herbicides reduced yellow nutsedge root and rhizome dry mass from 39 to 98%, number of new tubers and tuber fresh weight from 38 to 100% and prevented re-emergence. Sequential applications of either herbicide within a three-week interval early post emergence is recommended for optimal control. Herbicide application to yellow nutsedge using halosulfuron and sulfentrazone should be made as early as possible postemergence, preferably at the three- to five-leaf stage or 200 to 250 growing degree days (GDD, 10 C base). Mowing can be an effective method to reduce yellow nutsedge growth. Mowing at 7.6 cm weekly reduced yellow nutsedge rhizome dry mass by 55% and number of new tubers formed by 63% in the greenhouse study. Physical removal of yellow nutsedge plants such as hand-pulling can be an effective method to manage yellow nutsedge and is most effective at the three- to five-leaf stage (200 to 250 GDD). End-users can maximize yellow nutsedge control by integrating early herbicide treatments and cultural practices such as mowing and hand-pulling.

Cyperus esculentus (yellow nutsedge).

The basal bulb and tubers are the organs for vegetative propagation of C. esculentus, as well as the short-lived rhizomes, which extend for 5-30 cm, or sometimes further, before turning up and forming a further shoot and basal bulb, or a dormant tuber. The rhizomes occasionally branch, but have no viable buds at their nodes, and they decay at the end of the growing season. The number of rhiozomes is unaffected by photoperiod but tuber formation is promoted in short photoperiods (Holm et al., 1977). In the southern USA, only new shoots and basal bulbs are formed at day lengths over 14 hours, whereas all rhizomes terminate in tubers as soon as days are shorter than 14 hours (Jansen, 1971).

High oil accumulation in tuber of yellow nutsedge compared to purple nutsedge is associated with more abundant expression of genes involved in fatty acid synthesis and triacylglycerol storage

Background Yellow nutsedge is a unique plant species that can accumulate up to 35% oil of tuber dry weight, perhaps the highest level observed in the tuber tissues of plant kingdom. To gain insight into the molecular mechanism that leads to high oil accumulation in yellow nutsedge, gene expression profiles of oil production pathways involved carbon metabolism, fatty acid synthesis, triacylglycerol synthesis, and triacylglycerol storage during tuber development were compared with purple nutsedge, the closest relative of yellow nutsedge that is poor in oil accumulation. Results Compared with purple nutsedge, high oil accumulation in yellow nutsedge was associated with significant up-regulation of specific key enzymes of plastidial RubisCO bypass as well as malate and pyruvate metabolism, almost all fatty acid synthesis enzymes, and seed-like oil-body proteins. However, overall transcripts for carbon metabolism toward carbon precursor for fatty acid synthesis were comparable and for triacylglycerol synthesis were similar in both species. Two seed-like master transcription factors ABI3 and WRI1 were found to display similar transcript patterns but were expressed at 6.5- and 14.3-fold higher levels in yellow nutsedge than in purple nutsedge, respectively. A weighted gene co-expression network analysis revealed that ABI3 was in strong transcriptional coordination with WRI1 and other key oil-related genes. Conclusions These results implied that pyruvate availability and fatty acid synthesis in plastid, along with triacylglycerol storage in oil bodies, rather than triacylglycerol synthesis in endoplasmic reticulum, are the major factors responsible for high oil production in tuber of yellow nutsedge, and ABI3 most likely plays a critical role in regulating oil accumulation. This study is of significance with regard to understanding the molecular mechanism controlling carbon partitioning toward oil production in oil-rich tuber and provides a valuable reference for enhancing oil accumulation in non-seed tissues of crops through genetic breeding or metabolic engineering.

High oil accumulation in tuber of yellow nutsedge compared to purple nutsedge is associated with more abundant expression of genes involved in fatty acid synthesis and triacylglycerol storage

Background: Yellow nutsedge is a unique plant species that can accumulate up to 35% oil of tuber dry weight, perhaps the highest level observed in the tuber tissues of plant kingdom. To gain insight into the molecular mechanism that leads to high oil accumulation in yellow nutsedge, gene expression profiles of oil production pathways involved carbon metabolism, fatty acid synthesis, triacylglycerol synthesis, and triacylglycerol storage during tuber development were compared with purple nutsedge, the closest relative of yellow nutsedge that is poor in oil accumulation. Results: Compared with purple nutsedge, high oil accumulation in yellow nutsedge was associated with significant up-regulation of specific key enzymes of plastidial Rubisco bypass as well as malate and pyruvate metabolism, almost all fatty acid synthesis enzymes, and seed-like oil-body proteins. However, overall transcripts for carbon metabolism toward carbon precursor for fatty acid synthesis were comparable and for triacylglycerol synthesis were similar in both species. Two seed-like master transcription factors ABI3 and WRI1 were found to display similar transcript patterns but were expressed at 6.5- and 14.3-fold higher levels in yellow nutsedge than in purple nutsedge, respectively. A weighted gene co-expression network analysis revealed that ABI3 was in strong transcriptional coordination with WRI1 and other key oil-related genes. Conclusions: These results implied that pyruvate availability and fatty acid synthesis in plastid, along with triacylglycerol storage in oil bodies, rather than triacylglycerol synthesis in endoplasmic reticulum, are the major factors responsible for high oil production in tuber of yellow nutsedge, and ABI3 most likely plays a critical role in regulating oil accumulation. This study is of significance with regard to understanding the molecular mechanism controlling carbon partitioning toward oil production in oil-rich tuber and provides a valuable reference for enhancing oil accumulation in non-seed tissues of crops through genetic breeding or metabolic engineering.

Interactions of Clomazone Plus Pendimethalin Mixed with Propanil in Rice

A study was conducted at the Louisiana State University Agricultural Center’s H. Rouse Caffey Rice Research Station in 2017 and 2018 to evaluate the interaction between a pre-package mixture of clomazone plus pendimethalin applied at 0, 760, 1145, or 1540 g ai ha-1 mixed with propanil at 0, 1120, 2240, or 4485 g ai ha-1. A synergistic response occurred when barnyardgrass was treated with all rates of clomazone plus pendimethalin mixed with either rate of propanil evaluated at 56 d after treatment. Unlike barnyardgrass, an antagonistic response occurred for yellow nutsedge control when treated with 760 and 1540 g ha-1 of clomazone plus pendimethalin mixed with 1120 or 2240 g ha-1 of propanil at 28 d after treatment; however, 1145 g ha-1 of clomazone plus pendimethalin mixed with 4485 g ha-1 of propanil resulted in a neutral interaction. At 28 d after treatment, Rice flatsedge treated with for all herbicide mixtures resulted in neutral interactions. The synergism of clomazone plus pendimethalin applied at 1540 g ha—1 mixed with propanil applied at 2240 or 4485 g ha-1 for barnyardgrass control resulted in an increased rough rice yield compared with 760 or 1145 g ha-1 of clomazone plus pendimethalin mixed with propanil applied at 1120 or 2240 g ha-1. These results indicate if barnyardgrass and rice flatsedge are present in a rice field the pre-package mixture of clomazone plus pendimethalin mixed with propanil can be an option for growers. However, if yellow nutsedge infest the area other herbicides may be needed.

Co-option of a seed-like proteome by oil-rich tubers

Co-option is an important aspect of evolution that can occur on several levels. Genes, whose function was molded by selection in the evolutionary past, are readily observed to serve a new function when acting in a different context in an extant system. Whole organs can be co-opted for new roles as well. For example, roots that evolved from shoot-like axes. Finally a framework of genes and its coded proteins can be co-opted to serve a similar molecular function but in a completely different organ, drastically changing its properties. Here, we describe such an example, where a set of proteins important for desiccation tolerance and oil accumulation in seeds of most angiosperms was co-opted in the tubers of yellow nutsedge (Cyperus esculentus). These tubers are not only desiccation tolerant but also store a large amount of lipids-especially TAG, similar to seeds. We generated nanoLC-MS/MS-based proteomes in five replicates of four stages of tuber development and compared them to the proteomes of roots and leaves, yielding 2257 distinct protein groups. Our data reveal a striking upregulation of hallmark proteins of seeds in the tubers. A deeper comparison to a previously published proteome of Arabidopsis seeds and seedlings indicate that indeed a seed-like proteome was co-opted. This was further supported by an analysis of the proteome of a lipid-droplet enriched fraction of yellow nutsedge, which also displayed seed-like characteristics.