Microbial symbionts buffer hosts from the demographic costs of environmental stochasticity.

Species' persistence in increasingly variable climates will depend on resilience against the fitness costs of environmental stochasticity. Most organisms host microbiota that shield against stressors. Here, we test the hypothesis that, by limiting exposure to temporally variable stressors, microbial symbionts reduce hosts' demographic variance. We parameterized stochastic population models using data from a 14-year symbiont-removal experiment including seven grass species that host Epichloë fungal endophytes. Results provide novel evidence that symbiotic benefits arise not only through improved mean fitness, but also through dampened inter-annual variance. Hosts with "fast" life-history traits benefited most from symbiont-mediated demographic buffering. Under current climate conditions, contributions of demographic buffering were modest compared to benefits to mean fitness. However, simulations of increased stochasticity amplified benefits of demographic buffering and made it the more important pathway of host-symbiont mutualism. Microbial-mediated variance buffering is likely an important, yet cryptic, mechanism of resilience in an increasingly variable world.

Fine-Mapping and Comparative Genomic Analysis Reveal the Gene Composition at the S and Z Self-incompatibility Loci in Grasses.

Self-incompatibility (SI) is a genetic mechanism of hermaphroditic plants to prevent inbreeding after self-pollination. Allogamous Poaceae species exhibit a unique gametophytic SI system controlled by two multi-allelic and independent loci, S and Z. Despite intense research efforts in the last decades, the genes that determine the initial recognition mechanism are yet to be identified. Here, we report the fine-mapping of the Z-locus in perennial ryegrass (Lolium perenne L.) and provide evidence that the pollen and stigma components are determined by two genes encoding DUF247 domain proteins (ZDUF247-I and ZDUF247-II) and the gene sZ, respectively. The pollen and stigma determinants are located side-by-side and were genetically linked in 10,245 individuals of two independent mapping populations segregating for Z. Moreover, they exhibited high allelic diversity as well as tissue-specific gene expression, matching the expected characteristics of SI determinants known from other systems. Revisiting the S-locus using the latest high-quality whole-genome assemblies revealed a similar gene composition and structure as found for Z, supporting the hypothesis of a duplicated origin of the two-locus SI system of grasses. Ultimately, comparative genomic analyses across a wide range of self-compatible and self-incompatible Poaceae species revealed that the absence of a functional copy of at least one of the six putative SI determinants is accompanied by a self-compatible phenotype. Our study provides new insights into the origin and evolution of the unique gametophytic SI system in one of the largest and economically most important plant families.

Identifying genomic regions associated with C4 photosynthetic activity and leaf anatomy in Alloteropsis semialata.

C4 photosynthesis is a complex trait requiring multiple developmental and metabolic alterations. Despite this complexity, it has independently evolved over 60 times. However, our understanding of the transition to C4 is complicated by the fact that variation in photosynthetic type is usually segregated between species that diverged a long time ago. Here, we perform a genome-wide association study (GWAS) using the grass Alloteropsis semialata, the only known species to have C3, intermediate, and C4 accessions that recently diverged. We aimed to identify genomic regions associated with the strength of the C4 cycle (measured using δ13C), and the development of C4 leaf anatomy. Genomic regions correlated with δ13C include regulators of C4 decarboxylation enzymes (RIPK), nonphotochemical quenching (SOQ1), and the development of Kranz anatomy (SCARECROW-LIKE). Regions associated with the development of C4 leaf anatomy in the intermediate individuals contain additional leaf anatomy regulators, including those responsible for vein patterning (GSL8) and meristem determinacy (GIF1). The parallel recruitment of paralogous leaf anatomy regulators between A. semialata and other C4 lineages implies the co-option of these genes is context-dependent, which likely has implications for the engineering of the C4 trait into C3 species.

Root responses to abiotic stress: a comparative look at root system architecture in maize and sorghum.

Under all environments, roots are important for plant anchorage and acquiring water and nutrients. However, there is a knowledge gap regarding how root architecture contributes to stress tolerance in a changing climate. Two closely related plant species, maize and sorghum, have distinct root system architectures and different levels of stress tolerance, making comparative analysis between these two species an ideal approach to resolve this knowledge gap. However, current research has focused on shared aspects of the root system that are advantageous under abiotic stress conditions rather than on differences. Here we summarize the current state of knowledge comparing the root system architecture relative to plant performance under water deficit, salt stress, and low phosphorus in maize and sorghum. Under water deficit, steeper root angles and deeper root systems are proposed to be advantageous for both species. In saline soils, a reduction in root length and root number has been described as advantageous, but this work is limited. Under low phosphorus, root systems that are shallow and wider are beneficial for topsoil foraging. Future work investigating the differences between these species will be critical for understanding the role of root system architecture in optimizing plant production for a changing global climate.

Genetic response of a perennial grass to warm and wet environments interacts and is associated with trait means as well as plasticity.

The potential for rapid evolution is an important mechanism allowing species to adapt to changing climatic conditions. Although such potential has been largely studied in various short-lived organisms, to what extent we can observe similar patterns in long-lived plant species, which often dominate natural systems, is largely unexplored. We explored the potential for rapid evolution in Festuca rubra, a long-lived grass with extensive clonal growth dominating in alpine grasslands. We used a field sowing experiment simulating expected climate change in our model region. Specifically, we exposed seeds from five independent seed sources to novel climatic conditions by shifting them along a natural climatic grid and explored the genetic profiles of established seedlings after 3 years. Data on genetic profiles of plants selected under different novel conditions indicate that different climate shifts select significantly different pools of genotypes from common seed pools. Increasing soil moisture was more important than increasing temperature or the interaction of the two climatic factors in selecting pressure. This can indicate negative genetic interaction in response to the combined effects or that the effects of different climates are interactive rather than additive. The selected alleles were found in genomic regions, likely affecting the function of specific genes or their expression. Many of these were also linked to morphological traits (mainly to trait plasticity), suggesting these changes may have a consequence on plant performance. Overall, these data indicate that even long-lived plant species may experience strong selection by climate, and their populations thus have the potential to rapidly adapt to these novel conditions.

Smut fungus (Langdonia walkerae) incidence is lower in two bunchgrass species (Aristida stricta and A. beyrichiana) after fires early in the year.

PREMISE: In frequently burned southeastern USA pine-grassland communities, wiregrass (Aristida stricta and A. beyrichiana) are dominant bunchgrasses whose flowers are infected during flowering by a smut fungus (Langdonia walkerae). We hypothesized that because prescribed fire timing affects wiregrass flowering patterns, it could affect smut incidence (occurrence of smut on plants) and severity of infection in inflorescences and spikelets. Because soil order could influence plant susceptibility, we hypothesized that these patterns would differ between soil orders. We hypothesized differences between species as representative of geographic variation in this ecosystem. METHODS: We surveyed the incidence and severity of L. walkerae in wiregrass populations (85 populations at 14 sites) that had been prescription burned at different times during the previous year. We used binomial regressions to test whether incidence and severity differed by burn day, soil order, or species, with site as a random effect. RESULTS: Fires that occurred in the winter were associated with significantly lower incidence than fires later in the year (as the months progressed into summer). Plants growing on Spodosol soils were significantly less likely to be infected than those on other soils. More variation in incidence, however, was explained by site, suggesting that site-specific characteristics were important. Smut severity in inflorescences and spikelets was greater overall in populations of A. stricta than in southern populations (A. beyrichiana). CONCLUSIONS: Our findings indicate that fire timing and soil order affect L. walkerae incidence in wiregrass plants, but neither appears to be associated with greater severity. Patterns of smut infection are related to site history and geographic variation.

Plant physical defenses contribute to a latitudinal gradient in resistance to insect herbivory within a widespread perennial grass.

PREMISE: Herbivore pressure can vary across the range of a species, resulting in different defensive strategies. If herbivory is greater at lower latitudes, plants may be better defended there, potentially driving a latitudinal gradient in defense. However, relationships that manifest across the entire range of a species may be confounded by differences within genetic subpopulations, which may obscure the drivers of these latitudinal gradients. METHODS: We grew plants of the widespread perennial grass Panicum virgatum in a common garden that included genotypes from three genetic subpopulations spanning an 18.5° latitudinal gradient. We then assessed defensive strategies of these plants by measuring two physical resistance traits-leaf mass per area (LMA) and leaf ash, a proxy for silica-and multiple measures of herbivory by caterpillars of the generalist herbivore fall armyworm (Spodoptera frugiperda). RESULTS: Across all genetic subpopulations, low-latitude plants experienced less herbivory than high-latitude plants. Within genetic subpopulations, however, this relationship was inconsistent-the most widely distributed and phenotypically variable subpopulation (Atlantic) exhibited more consistent latitudinal trends than either of the other two subpopulations. The two physical resistance traits, LMA and leaf ash, were both highly heritable and positively associated with resistance to different measures of herbivory across all subpopulations, indicating their importance in defense against herbivores. Again, however, these relationships were inconsistent within subpopulations. CONCLUSIONS: Defensive gradients that occur across the entire species range may not arise within localized subpopulations. Thus, identifying the drivers of latitudinal gradients in herbivory defense may depend on adequately sampling the diversity within a species.

Investigating historical drivers of latitudinal gradients in polyploid plant biogeography: A multiclade perspective.

PREMISE: The proportion of polyploid plants in a community increases with latitude, and different hypotheses have been proposed about which factors drive this pattern. Here, we aimed to understand the historical causes of the latitudinal polyploidy gradient using a combination of ancestral state reconstruction methods. Specifically, we assessed whether (1) polyploidization enables movement to higher latitudes (i.e., polyploidization precedes occurrences in higher latitudes) or (2) higher latitudes facilitate polyploidization (i.e., occurrence in higher latitudes precedes polyploidization). METHODS: We reconstructed the ploidy states and ancestral niches of 1032 angiosperm species at four paleoclimatic time slices ranging from 3.3 million years ago to the present, comprising taxa from four well-represented clades: Onagraceae, Primulaceae, Solanum (Solanaceae), and Pooideae (Poaceae). We used ancestral niche reconstruction models alongside a customized discrete character evolution model to allow reconstruction of states at specific time slices. Patterns of latitudinal movement were reconstructed and compared in relation to inferred ploidy shifts. RESULTS: No single hypothesis applied equally well across all analyzed clades. While significant differences in median latitudinal occurrence were detected in the largest clade, Poaceae, no significant differences were detected in latitudinal movement in any clade. CONCLUSIONS: Our preliminary study is the first to attempt to connect ploidy changes to continuous latitudinal movement, but we cannot favor one hypothesis over another. Given that patterns seem to be clade-specific, more clades must be analyzed in future studies for generalities to be drawn.

Genetically correlated leaf tensile and morphological traits are driven by growing season length in a widespread perennial grass.

PREMISE: Leaf tensile resistance, a leaf's ability to withstand pulling forces, is an important determinant of plant ecological strategies. One potential driver of leaf tensile resistance is growing season length. When growing seasons are long, strong leaves, which often require more time and resources to construct than weak leaves, may be more advantageous than when growing seasons are short. Growing season length and other ecological conditions may also impact the morphological traits that underlie leaf tensile resistance. METHODS: To understand variation in leaf tensile resistance, we measured size-dependent leaf strength and size-independent leaf toughness in diverse genotypes of the widespread perennial grass Panicum virgatum (switchgrass) in a common garden. We then used quantitative genetic approaches to estimate the heritability of leaf tensile resistance and whether there were genetic correlations between leaf tensile resistance and other morphological traits. RESULTS: Leaf tensile resistance was positively associated with aboveground biomass (a proxy for fitness). Moreover, both measures of leaf tensile resistance exhibited high heritability and were positively genetically correlated with leaf lamina thickness and leaf mass per area (LMA). Leaf tensile resistance also increased with the growing season length in the habitat of origin, and this effect was mediated by both LMA and leaf thickness. CONCLUSIONS: Differences in growing season length may promote selection for different leaf lifespans and may explain existing variation in leaf tensile resistance in P. virgatum. In addition, the high heritability of leaf tensile resistance suggests that P. virgatum will be able to respond to climate change as growing seasons lengthen.

Environmental DNA analysis of airborne poaceae (grass) pollen reveals taxonomic diversity across seasons and climate zones.

BACKGROUND: Grasses populate most biogeographical zones, and their diversity influences allergic sensitisation to pollen. Previously, the contribution of different Poaceae subfamilies to airborne pollen has mostly been inferred from historical herbarium records. We recently applied environmental (e)DNA metabarcoding at one subtropical site revealing that successive airborne grass pollen peaks were derived from repeated flowering of Chloridoid and Panicoid grasses over a season. This study aimed to compare spatiotemporal patterns in grass pollen exposure across seasons and climate zones. METHODS: Airborne pollen concentrations across two austral pollen seasons spanning 2017-2019 at subtropical (Mutdapilly and Rocklea, Queensland) and temperate (Macquarie Park and Richmond, New South Wales) sites, were determined with a routine volumetric impaction sampler and counting by light microscopy. Poaceae rbcL metabarcode sequences amplified from daily pollen samples collected once per week were assigned to subfamily and genus using a ribosomal classifier and compared with Atlas of Living Australia sighting records. RESULTS: eDNA analysis revealed distinct dominance patterns of grass pollen at various sites: Panicoid grasses prevailed in both subtropical Mutdapilly and temperate Macquarie Park, whilst Chloridoid grasses dominated the subtropical Rocklea site. Overall, subtropical sites showed significantly higher proportion of pollen from Chloridoid grasses than temperate sites, whereas the temperate sites showed a significantly higher proportion of pollen from Pooideae grasses than subtropical sites. Timing of airborne Pooid (spring), Panicoid and Chloridoid (late spring to autumn), and Arundinoid (autumn) pollen were significantly related to number of days from mid-winter. Proportions of eDNA for subfamilies correlated with distributions grass sighting records between climate zones. CONCLUSIONS: eDNA analysis enabled finer taxonomic discernment of Poaceae pollen records across seasons and climate zones with implications for understanding adaptation of grasslands to climate change, and the complexity of pollen exposure for patients with allergic respiratory diseases.

Five new glycosides from the culms of Phyllostachys nigra var. henonis.

Five new glycosides, namely methyl 3-methoxybenzoate-4,5-di-O-ß-D-glucopyranoside (1), (1aS,3aS,3R)-3-(4'-O-ß-D-glucopyranosyl-3'-methoxyphenyl)-5,6-dioxa-bicyclo[3.3.0]octane-1-one (2), quinolin-4(1H)-one-3-O-ß-D-glucopyranoside (3), 3-methoxy-propiophenone 4-O-(6'-ß-D-xylopyranosyl)-ß-D-glucopyranoside (4), methyl 3-methoxybenzoate 4-O-(6'-ß-D-xylopyranosyl)-ß-D-glucopyranoside (5), and one known compound, bambulignan B (6) were isolated from the culms of Phyllostachys nigra var. henonis. Their structures were determined using spectroscopic analysis. All compounds were evaluated for their DPPH radical scavenging activity. Compound 6 exhibited antioxidant activity with IC50 value of 59.5 µM (positive control, L-ascorbic acid, IC50 = 12.4 µM; 2,6-ditertbutyl-4-methyl phenol, IC50 = 11.8 µM).

Plants of Different Monocot Families Differ in Nitrogen and Phosphorus Contents in Leaves.

The folia content of nitrogen (N) and phosphorus (P) were studied in five monocot families: Amaryllidaceae, Cyperaceae, Iridaceae, Orchidacea, and Poaceae. The species of different monocot families were found to have different amount of N and P and their ratio in the leaves. The lowest N content was in Iridaceae and the highest was in Amaryllidaceae. The lowest P content was in Cyperaceae and Poaceae while the highest was in Amaryllidaceae and Iridaceae. A minimum N/P ratio was observed in Iridaceae; a maximum N/P ratio, was in Poaceae. Thus, certain specifics were detected in the content of N and P and their ratio in the monocot families.

Lateral gene transfer generates accessory genes that accumulate at different rates within a grass lineage.

Lateral gene transfer (LGT) is the movement of DNA between organisms without sexual reproduction. The acquired genes represent genetic novelties that have independently evolved in the donor's genome. Phylogenetic methods have shown that LGT is widespread across the entire grass family, although we know little about the underlying dynamics. We identify laterally acquired genes in five de novo reference genomes from the same grass genus (four Alloteropsis semialata and one Alloteropsis angusta). Using additional resequencing data for a further 40 Alloteropsis individuals, we place the acquisition of each gene onto a phylogeny using stochastic character mapping, and then infer rates of gains and losses. We detect 168 laterally acquired genes in the five reference genomes (32-100 per genome). Exponential decay models indicate that the rate of LGT acquisitions (6-28 per Ma) and subsequent losses (11-24% per Ma) varied significantly among lineages. Laterally acquired genes were lost at a higher rate than vertically inherited loci (0.02-0.8% per Ma). This high turnover creates intraspecific gene content variation, with a preponderance of them occurring as accessory genes in the Alloteropsis pangenome. This rapid turnover generates standing variation that can ultimately fuel local adaptation.

Auxins and grass shoot architecture: how the most important hormone makes the most important plants.

Cereals are a group of grasses cultivated by humans for their grain. It is from these cereal grains that the majority of all calories consumed by humans are derived. The production of these grains is the result of the development of a series of hierarchical reproductive structures that form the distinct shoot architecture of the grasses. Being spatiotemporally complex, the coordination of grass shoot development is tightly controlled by a network of genes and signals, including the key phytohormone auxin. Hormonal manipulation has therefore been identified as a promising potential approach to increasing cereal crop yields and therefore ultimately global food security. Recent work translating the substantial body of auxin research from model plants into cereal crop species is revealing the contribution of auxin biosynthesis, transport, and signalling to the development of grass shoot architecture. This review discusses this still-maturing knowledge base and examines the possibility that changes in auxin biology could have been a causative agent in the evolution of differences in shoot architecture between key grass species, or could underpin the future selective breeding of cereal crops.

Alloteropsis semialata as a study system for C4 evolution in grasses.

BACKGROUND: Numerous groups of plants have adapted to CO2 limitations by independently evolving C4 photosynthesis. This trait relies on concerted changes in anatomy and biochemistry to concentrate CO2 within the leaf and thereby boost productivity in tropical conditions. The ecological and economic importance of C4 photosynthesis has motivated intense research, often relying on comparisons between distantly related C4 and non-C4 plants. The photosynthetic type is fixed in most species, with the notable exception of the grass Alloteropsis semialata. This species includes populations exhibiting the ancestral C3 state in southern Africa, intermediate populations in the Zambezian region and C4 populations spread around the palaeotropics. SCOPE: We compile here the knowledge on the distribution and evolutionary history of the Alloteropsis genus as a whole and discuss how this has furthered our understanding of C4 evolution. We then present a chromosome-level reference genome for a C3 individual and compare the genomic architecture with that of a C4 accession of A. semialata. CONCLUSIONS: Alloteropsis semialata is one of the best systems in which to investigate the evolution of C4 photosynthesis because the genetic and phenotypic variation provides a fertile ground for comparative and population-level studies. Preliminary comparative genomic investigations show that the C3 and C4 genomes are highly syntenic and have undergone a modest amount of gene duplication and translocation since the different photosynthetic groups diverged. The background knowledge and publicly available genomic resources make A. semialata a great model for further comparative analyses of photosynthetic diversification.

Sequencing and biological characterization of historical cynosurus mottle virus isolates from Germany.

We report sequencing of four historical cynosurus mottle virus (CnMoV) isolates, originating from different hosts and locations. The CnMoV genome, ranging from 4417 to 4419 nt, encodes five ORFs. It shares 48.1% nucleotide sequence identity with cocksfoot mottle virus and 69.8% with the recently discovered Poaceae Liege sobemovirus. Phylogenetic analysis supports classification within the genus Sobemovirus. Sequenced CnMoV isolates exhibit 96.4-99.9% identity. Nucleotide substitutions leading to amino acid changes showed no host associations. However, amino acid changes in the coat protein appear to be linked to differences in serological properties. Aphid transmission tests confirmed non-transmissibility, consistent with earlier observations for the English isolate.

Poaceae Chloroplast Genome Sequencing: Great Leap Forward in Recent Ten Years.

The first complete chloroplast genome of rice (Oryza sativa) was published in 1989, ushering in a new era of studies of chloroplast genomics in Poaceae. Progresses in Next-Generation Sequencing (NGS) and Third-Generation Sequencing (TGS) technologiesand in the development of genome assembly software, have significantly advanced chloroplast genomics research. Poaceae is one of the most targeted families in chloroplast genome research because of its agricultural, ecological, and economic importance. Over the last 30 years, 2,050 complete chloroplast genome sequences from 40 tribes and 282 genera have been generated, most (97%) of them in the recent ten years. The wealth of data provides the groundwork for studies on species evolution, phylogeny, genetic transformation, and other aspects of Poaceae chloroplast genomes. As a result, we have gained a deeper understanding of the properties of Poaceae chloroplast genomes. Here, we summarize the achievements of the studies of the Poaceae chloroplast genomes and envision the challenges for moving the area ahead.

Exogenous Nitric Oxide Alleviates Water Deficit and Increases the Seed Production of an Endemic Amazonian Canga Grass.

Open pit mining can cause loss in different ecosystems, including damage to habitats of rare and endemic species. Understanding the biology of these species is fundamental for their conservation, and to assist in decision-making. Sporobolus multiramosus is an annual grass endemic to the Amazon canga ecosystems, which comprise rocky outcrop vegetation covering one of the world's largest iron ore reserves. Here, we evaluated whether nitric oxide aids S. multiramosus in coping with water shortages and examined the physiological processes behind these adaptations. nitric oxide application improved the water status, photosynthetic efficiency, biomass production, and seed production and germination of S. multiramosus under water deficit conditions. These enhancements were accompanied by adjustments in leaf and root anatomy, including changes in stomata density and size and root endodermis thickness and vascular cylinder diameter. Proteomic analysis revealed that nitric oxide promoted the activation of several proteins involved in the response to environmental stress and flower and fruit development. Overall, the results suggest that exogenous nitric oxide has the potential to enhance the growth and productivity of S. multiramosus. Enhancements in seed productivity have significant implications for conservation initiatives and can be applied to seed production areas, particularly for the restoration of native ecosystems.

Rehabilitation of eroded trails and gullies on quartzite rock outcrops with native species in a high-altitude grassland.

The quartzite rock outcrops and the native vegetation of grasslands located at the Serra da Calçada Mountain in Minas Gerais State (Brazil) have been severely degraded by extreme sports activities such as motocross and off-road vehicles, greatly damaging the abundant headwaters. The main consequences thereof were hilly and gully erosion processes with soil loss and the deviation of the water from its original paths. However, currently, there is no report of successful restoration efforts in severely eroded outcrops in Brazilian high-altitude grasslands (campo rupestre). Through the Universal Soil Loss Equation (USLE), we found a high general erosion rate in the study site (669.91 t·ha-1·year-1), and the specific soil loss provoked by off-road vehicles on trails was significantly greater (49 m3 per 100 m2) than that caused by mountain bikes and trekking (5.8 m3 per 100 m2). We performed the physical reconstruction of eroded outcrops and surface water flow paths by allocating locally available quartzite rocks. These rocks were inoculated with different species of bryophytes and planted with native species under two treatments: un-inoculated and inoculated with arbuscular mycorrhizal fungi (AMF) spores of the Rhizophagus irregularis species. After 2 years, the bryophyte communities showed a similar pattern to the preserved site, and the AMF inoculation favoured plant establishment of most species, especially of the Asteraceae, Cyperaceae, Fabaceae, Malpighiaceae, Orchidaceae and Poaceae families. The AMF also improved the soil fertility, highlighting soil P, SOM, CEC, NH4+-N as well as soil water content and water retention capacity. Poaceae family species showed an outstanding occupation, which was considered a functional indicator of rehabilitation success, functioning as a "hydraulic carpet" for water exportation, conduction and drainage across the outcrops. This study provides an eco-technology to restore severely eroded outcrops over headwaters using native species in the Brazilian high-altitude grasslands.

Genetic mapping identifies a rice naringenin O-glucosyltransferase that influences insect resistance.

Naringenin, the biochemical precursor for predominant flavonoids in grasses, provides protection against UV damage, pathogen infection and insect feeding. To identify previously unknown loci influencing naringenin accumulation in rice (Oryza sativa), recombinant inbred lines derived from the Nipponbare and IR64 cultivars were used to map a quantitative trait locus (QTL) for naringenin abundance to a region of 50 genes on rice chromosome 7. Examination of candidate genes in the QTL confidence interval identified four predicted uridine diphosphate-dependent glucosyltransferases (Os07g31960, Os07g32010, Os07g32020 and Os07g32060). In vitro assays demonstrated that one of these genes, Os07g32020 (UGT707A3), encodes a glucosyltransferase that converts naringenin and uridine diphosphate-glucose to naringenin-7-O-ß-d-glucoside. The function of Os07g32020 was verified with CRISPR/Cas9 mutant lines, which accumulated more naringenin and less naringenin-7-O-ß-d-glucoside and apigenin-7-O-ß-d-glucoside than wild-type Nipponbare. Expression of Os12g13800, which encodes a naringenin 7-O-methyltransferase that produces sakuranetin, was elevated in the mutant lines after treatment with methyl jasmonate and insect pests, Spodoptera litura (cotton leafworm), Oxya hyla intricata (rice grasshopper) and Nilaparvata lugens (brown planthopper), leading to a higher accumulation of sakuranetin. Feeding damage from O. hyla intricata and N. lugens was reduced on the Os07g32020 mutant lines relative to Nipponbare. Modification of the Os07g32020 gene could be used to increase the production of naringenin and sakuranetin rice flavonoids in a more targeted manner. These findings may open up new opportunities for selective breeding of this important rice metabolic trait.