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Wild crop germplasm and landrace varieties have long been considered as a source of novel genetic variation for improving domesticated crops. Due to genetic bottlenecks that occurred during domestication, dissemination, and subsequent crop improvement, many beneficial genes are absent from commercial varieties and elite breeding germplasm, yet are still present in wild populations. To catalog potential novel disease resistance genes useful for breeding more resilient dry beans, we screened wild and landrace Phaseolus vulgaris L. accessions archived in the USDA GRIN seed bank for untapped resistance to anthracnose (Colletotrichum lindemuthianum) and bean common mosaic necrosis virus (BCMNV). A population of 194 wild and 55 landrace accessions were screened for resistance to two highly virulent races of anthracnose (race 2047 and race 3481) and for resistance to the BCMNV strain NL‐3. Thirteen accessions, all wild, were resistant to both anthracnose races, with MX‐QT‐3 and PI 661812 displaying complete resistance with no disease symptoms across all replications. Surprisingly, no natural resistance to BCMNV strain NL‐3 was detected in the wild germplasm. PI 442541, PI 661891, and W6 10164 were the only three accessions that expressed the I‐gene phenotype and all three have some history of cultivation. This study provides a resource for introgression of genetic diversity for anthracnose resistance into cultivated beans and reveals that innate resistance to BCMNV may not exist in wild populations of P. vulgaris. Core Ideas: Wild Phaseolus vulgaris germplasm has genetic and phenotypic diversity not present in cultivated varieties.Resistance to two races of anthracnose exists in wild bean germplasm.Resistance to BCMNV NL‐3 was not found in wild bean germplasm, but in three landraces. [ABSTRACT FROM AUTHOR]

Endoparasitism by gall-forming insects dramatically alters the plant phenotype by altering growth patterns and modifying plant organs in ways that appear to directly benefit the gall former. Because these morphological and physiological changes are linked to the presence of the insect, the induced phenotype is said to function as an extension of the parasite, albeit by unknown mechanisms. Here we report the gall-forming aphid-like parasite phylloxera, Daktulosphaira vitifoliae, induces stomata on the adaxial surface of grape leaves where stomata typically do not occur. We characterized the function of the phylloxera-induced stomata by tracing transport of assimilated carbon. Because induction of stomata suggests a significant manipulation of primary metabolism, we also characterized the gall transcriptome to infer the level of global reconfiguration of primary metabolism and the subsequent changes in downstream secondary metabolism. Phylloxera feeding induced stomata formation in proximity to the insect and promoted the assimilation and importation of carbon into the gall. Gene expression related to water, nutrient, and mineral transport; glycolysis; and fermentation increased in leaf-gall tissues. This shift from an autotrophic to a heterotrophic profile occurred concurrently with decreased gene expression for nonmevalonate and terpenoid synthesis and increased gene expression in shikimate and phenylpropanoid biosynthesis, secondary metabolite systems that alter defense status in grapes. These functional insect-induced stomata thus comprise part of an extended phenotype, whereby D. vitifoliae globally reprograms grape leaf development to alter patterns of primary metabolism, nutrient mobilization, and defense investment in favor of the galling habit.

Abstract Background Sacred lotus is a basal eudicot with agricultural, medicinal, cultural and religious importance. It was domesticated in Asia about 7,000 years ago, and cultivated for its rhizomes and seeds as a food crop. It is particularly noted for its 1,300-year seed longevity and exceptional water repellency, known as the lotus effect. The latter property is due to the nanoscopic closely packed protuberances of its self-cleaning leaf surface, which have been adapted for the manufacture of a self-cleaning industrial paint, Lotusan. Results The genome of the China Antique variety of the sacred lotus was sequenced with Illumina and 454 technologies, at respective depths of 101× and 5.2×. The final assembly has a contig N50 of 38.8 kbp and a scaffold N50 of 3.4 Mbp, and covers 86.5% of the estimated 929 Mbp total genome size. The genome notably lacks the paleo-triplication observed in other eudicots, but reveals a lineage-specific duplication. The genome has evidence of slow evolution, with a 30% slower nucleotide mutation rate than observed in grape. Comparisons of the available sequenced genomes suggest a minimum gene set for vascular plants of 4,223 genes. Strikingly, the sacred lotus has 16 COG2132 multi-copper oxidase family proteins with root-specific expression; these are involved in root meristem phosphate starvation, reflecting adaptation to limited nutrient availability in an aquatic environment. Conclusions The slow nucleotide substitution rate makes the sacred lotus a better resource than the current standard, grape, for reconstructing the pan-eudicot genome, and should therefore accelerate comparative analysis between eudicots and monocots.

Stomata control water loss and carbon dioxide uptake by both altering pore aperture and developmental patterning. Stomatal patterning is regulated by environmental factors including atmospheric carbon dioxide (p [CO2]), which is increasing globally at an unprecedented rate. Mature leaves are known to convey developmental cues to immature leaves in response to p [CO2], but the developmental mechanisms are unknown. To characterize changes in stomatal patterning resulting from signals moving from mature to developing leaves, we constructed a dual-chamber growth system in which rosette and cauline leaves of Arabidopsis thaliana were subjected to differing p [CO2]. Young rosette tissue was found to adjust stomatal index (SI, the proportion of stomata to total cell number) in response to both the current environment and the environment experienced by mature rosette tissue, whereas cauline leaves appear to be insensitive to p [CO2] treatment. It is likely that cauline leaves and cotyledons deploy mechanisms for controlling stomatal development that share common but also deploy distinctive mechanisms to that operating in rosette leaves. The effect of p [CO2] on stomatal development is retained in cotyledons of the next generation, however, this effect does not occur in pre-germination stomatal lineage cells but only after germination. Finally, these data suggest that p [CO2] affects regulation of stomatal development specifically through the development of satellite stomata (stomata induced by signals from a neighboring stomate) during spacing divisions and not the basal pathway. To our knowledge, this is the first report identifying developmental steps responsible for altered stomatal patterning to p [CO2] and its trans-generational inheritance. [ABSTRACT FROM AUTHOR]

Peach ( Prunus persica ) trees with a mutation in the weep gene exhibit a weeping branch phenotype. In contrast, Arabidopsis ( Arabidopsis thaliana ) weep mutants do not have a shoot architecture phenotype. A recent report revealed that barley ( Hordeum vulgare ) and wheat ( Triticum aestivum ) with mutations in EGT2, a WEEP homolog, have steeper root angles than standard varieties. We investigated the root architecture of three Arabidopsis weep mutant lines. All three lines exhibited steeper root angles and a smaller convex hull area, indicating that the total area explored by the root system is reduced. These results reveal WEEP is important for regulating lateral root angles in a dicot., (Copyright: © 2022 by the authors.)

Stomata control water loss and carbon dioxide uptake by both altering pore aperture and developmental patterning. Stomatal patterning is regulated by environmental factors including atmospheric carbon dioxide ( p [CO 2 ]), which is increasing globally at an unprecedented rate. Mature leaves are known to convey developmental cues to immature leaves in response to p [CO 2 ], but the developmental mechanisms are unknown. To characterize changes in stomatal patterning resulting from signals moving from mature to developing leaves, we constructed a dual-chamber growth system in which rosette and cauline leaves of Arabidopsis thaliana were subjected to differing p [CO 2 ]. Young rosette tissue was found to adjust stomatal index (SI, the proportion of stomata to total cell number) in response to both the current environment and the environment experienced by mature rosette tissue, whereas cauline leaves appear to be insensitive to p [CO 2 ] treatment. It is likely that cauline leaves and cotyledons deploy mechanisms for controlling stomatal development that share common but also deploy distinctive mechanisms to that operating in rosette leaves. The effect of p [CO 2 ] on stomatal development is retained in cotyledons of the next generation, however, this effect does not occur in pre-germination stomatal lineage cells but only after germination. Finally, these data suggest that p [CO 2 ] affects regulation of stomatal development specifically through the development of satellite stomata (stomata induced by signals from a neighboring stomate) during spacing divisions and not the basal pathway. To our knowledge, this is the first report identifying developmental steps responsible for altered stomatal patterning to p [CO 2 ] and its trans-generational inheritance.