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The extreme diversity and complexity of angiosperms is well known. Despite the fact that parasitic plants are angiosperms, little is known about parasitic plant mitogenomic diversity, complexity, and evolution. In this study, we obtained and characterized the mitogenomes of three Cistanche species (holoparasitic plants) from China to compare the repeats, segment duplication and multi-copy protein-coding genes (PCGs), to clarify the phylogenetic and evolution relationship within the Lamiales order, and to identify the mitochondrial plastid insertions (MTPT) in Cistanche mitogenomes. The results showed that the mitogenome sizes of the three Cistanche species ranged from 1,708,661 to 3,978,341 bp. The Cistanche species genome encodes 75–126 genes, including 37–65 PCGs, 31–58 tRNA genes and 3–5 rRNA genes. Compared with other Lamiales and parasitic species, the Cistanche species showed extremely high rates of multi-copy PCGs, ranging from 0.13 to 0.58 percent of the total number of PCGs. In addition, 37–133 Simple Sequence Repeat (SSRs) were found in these three mitogenomes, the majority of which were the mononucleotides Adenine/Thymine. The interspersed repeats contained forward and palindromic repeats. Furthermore, the segment-duplication sequence size ranged from 199,584 to 2,142,551 bp, accounting for 24.9%, 11.7% and 53.9% of the Cistanche deserticola, Cistanche salsa and Cistanche tubulosa mitogenome, respectively. Furthermore, the Ka/Ks analysis suggested that the atp4, ccmB, ccmFc and matR were probably positively selected during Lamiales evolution. The Cistanche plastome suggested the presence of MTPT. Moreover, 6–12 tRNA, 9–15 PCGs fragments and 3 rRNA gene fragments in the Cistanche mitogenomes were found in the MTPT regions. This work reports the Cistanche species mitogenome for the first time, which will be invaluable for study the mitogenome evolution of Orobanchaceae family. [ABSTRACT FROM AUTHOR]

Agricultural ecosystems are one of the most severely disturbed habitats, which are seriously infestated by invasive alien species. In particular, there has not been a systematic review on the aspect of alien invasive plants in agricultural ecosystems in China. Therefore, based on field investigations and literature reviews, the present status of invasion and managements of alien plants in agricultural ecosystems in China was systematically summarized in order to provide information for establishing reasonable control strategies and the ongoing national census of invasive species. At present, there were a total of 331 species and 5 varieties of invasive alien plants belonging to 187 genera, 52 families in China. The main life forms were annual plants(209 species, 62.20% of the total species)and perennial plants(132 species, 39.29% of the total species),followed by perennial plants(121 species, 36.01% of the total species),shrubs and semi-shrubs were rare. The ecological type was dominated by mesophytes plants(271 species, 80.65% of the total species),and there were few xerophytes, hydrophytes, aquatic and parasitic plants. The floristic composition included 10 zones and 7 subzones. The number of plants that naturalized after intentional introduction account for 50.60% of the total species, and both the number of species and the place of first introduction showed a decreasing trend from the southeast coast to the northwest inland. Invasive plants mainly came from the America(64.58%),followed by Europe(23.81%),Asia(15.48%),Africa(13.69%),and Oceania(0.89%). The most invasive alien plant species infested vegetable fields(83.33%)and orchards(66.37%),then autumn-harvested crop drylands(59.52%),summer-harvested crop dryland(51.19%). According to their harmfulness, invasive alien plants were classified into four groups, in which malignant weeds(22 species)and regional malignant weeds(53 species)were the key targets for the control of invasive alien plants in farmland. Today, over-uses of chemical herbicides has led to the evolution of herbicide-resistant biotypes in 60 invasive plants in different regions of the world. In the future, attention should be paid to border quarantine, biological, ecological and other comprehensive prevention and control. It is also necessary to strengthen the researches on the invasion history, pathway, distribution, mechanism and trend of alien species to the agricultural ecosystem, and monitor the impact of invasive species and herbicide-resistant biotypes on the succession of agricultural pest communities. [ABSTRACT FROM AUTHOR]

Climate change affects parasitic plants and their hosts on distributions. However, little is known about how parasites and their hosts shift in distribution, and niche overlap in response to global change remains unclear to date. Here, the potential distribution and habitat suitability of four endangered holoparasites and their primary hosts in northern China were predicted using MaxEnt based on occurrence records and bioclimatic variables. The results indicated that (1) Temperature annual range (Bio7) and Precipitation of driest quarter (Bio17) were identified as the common key climatic factors influencing distribution (percentage contribution > 10%) for Cynomorium songaricum vs. Nitraria sibirica (i.e., parasite vs. host); Temperature seasonality (Bio4) and Precipitation of driest month (Bio14) for Boschniakia rossica vs. Alnus mandshurica; Bio4 for Cistanche deserticola vs. Haloxylon ammodendron; Precipitation of warmest quarter (Bio18) for Cistanche mongolica vs. Tamarix ramosissima. Accordingly, different parasite-host pairs share to varying degree the common climatic factors. (2) Currently, these holoparasites had small suitable habitats (i.e., moderately and highly) (0.97–3.77%), with few highly suitable habitats (0.19– 0.81%). Under future scenarios, their suitable habitats would change to some extent; their distribution shifts fell into two categories: growing type (Boschniakia rossica and Cistanche mongolica) and fluctuating type (Cynomorium songaricum and Cistanche deserticola). In contrast, the hosts’ current suitable habitats (1.42–13.43%) varied greatly, with highly restricted suitable habitats (0.18–1.00%). Under future scenarios, their suitable habitats presented different trends: growing type (Nitraria sibirica), declining type (Haloxylon ammodendron) and fluctuating type (the other hosts). (3) The niche overlaps between parasites and hosts differed significantly in the future, which can be grouped into two categories: growing type (Boschniakia rossica vs. Alnus mandshurica, Cistanche mongolica vs. Tamarix ramosissima), and fluctuating type (the others). Such niche overlap asynchronies may result in severe spatial limitations of parasites under future climate conditions. Our findings indicate that climate factors restricting parasites and hosts’ distributions, niche overlaps between them, together with parasitic species identity, may jointly influence the suitable habitats of parasitic plants. Therefore, it is necessary to take into account the threatened holoparasites themselves in conjunction with their suitable habitats and the parasite-host association when developing conservation planning in the future. [ABSTRACT FROM AUTHOR]

Parasitic broomrape of the genus Orobanche poses a formidable threat to producing many crops in Europe, Africa, and Asia. Orobanche cumana and Phelipanche aegyptiaca are two of China's most destructive root parasitic plants, causing extreme sunflower, tomato, melon, and tobacco damage. However, the potentially suitable areas of O. cumana and P. aegyptiaca in China have not been predicted, and little is known about the important environmental factors that affect their extension. Due to their invasiveness and economic importance, studying how climate change and host plants may affect broomrapes' distribution is necessary. In the study, we first predicted the potentially suitable areas of the invasive weeds (O. cumana and P. aegyptiaca) and their susceptible host plants (Helianthus annuus and Solanum lycopersicon) using MaxEnt. Then, the risk zones and distribution shifts of two broomrapes under different climate conditions were identified by incorporating the distribution of their susceptible host plants. The results highlighted that the potential middle‐ and high‐risk zones for O. cumana and P. aegyptiaca amounted to 197.88 × 104 km2 and 12.90 × 104 km2, respectively. Notably, Xinjiang and Inner Mongolia were the highest‐risk areas within the distribution and establishment of O. cumana and P. aegyptiaca. Elevation and topsoil pH were the decisive factors for shaping O. cumana distribution; precipitation seasonality and annual precipitation were the dominant bioclimatic variables limiting the spread of P. aegyptiaca. The potentially suitable areas and risk zones of O. cumana would decrease significantly, and those of P. aegyptiaca would fluctuate slightly under future climate change scenarios. Overall, our study suggested that the two broomrapes' risk zones will significantly northward to higher latitudes. The results will provide suggestions for preventing O. cumana and P. aegyptiaca. [ABSTRACT FROM AUTHOR]

Background: The climate is the dominant factor that affects the distribution of plants. Cuscuta chinensis is a stem holoparasitic plant without leaves or roots, which develops a haustorium and sucks nutrients from host plants. The potential distribution of the parasitic plant C. chinensis has not been predicted to date. This study used Maxent modeling to predict the potential global distribution of C. chinensis, based on the following six main bioclimatic variables: annual mean temperature, isothermality, temperature seasonality, precipitation seasonality, precipitation of the warmest quarter, and precipitation of the coldest quarter. Results: The optimal annual average temperature and isothermality of C. chinensis ranged from 4 to 37 °C and less than 45, respectively, while the optimal temperature seasonality and precipitation seasonality ranged from 4000 to 25,000 and from 50 to 130, respectively. The optimal precipitation of the warmest season ranged from 300 to 1000 mm and from 2500 to 3500 mm, while that of the coldest season was less than 2000 mm. In Asia, C. chinensis is mainly distributed at latitudes ranging from 20° N to 50° N. During three specific historical periods (last glacial maximum, mid-Holocene, and 1960–1990) the habitats suitable for C. chinensis were concentrated in the central, northern, southern, and eastern parts of China. From the last glacial maximum to the mid-Holocene, the total area with suitability of 0.5–1 increased by 0.0875 million km2; however, from the mid-Holocene to 1960–1990, the total area with suitability of 0.5–1 decreased by 0.0759 million km2. The simulation results of habitat suitability in the two representative concentration pathways (RCP) 2.6 (i.e., the low greenhouse gas emissions pathway) and 8.5 (i.e., the high greenhouse gas emissions pathway) indicate that the habitat suitability of C. chinensis decreased in response to the warming climate. Compared with RCP2.6, areas with averaged suitability and high suitability for survival (RCP8.5) decreased by 0.18 million km2. Conclusion: Suitable habitats of C. chinensis are situated in central, northern, southern, and eastern China. The habitat suitability of C. chinensis decreased in response to the warming climate. These results provide a reference for the management and control of C. chinensis. [ABSTRACT FROM AUTHOR]

Prostrate knotweed (Polygonum aviculare L.) is a persistent native weed of China. This weed is characterized by high genetic and biological plasticity having a capacity to spread on a landscape scale. The present study planned to investigate the infection of a plant parasitic powdery mildew on P. aviculare on a landscape scale in three different locations of Shenyang during 2018. These locations were selected with a control treatment for proper comparison. Different growth parameters were observed and calculated by coefficient of determination ( R2). Maximum temperature (Maxt) ranged 25-30 °C and Minimum temperature (Mint) between 17 -20 °C with relative humidity 64-78% played a vital role for the emergence and flourishing of pathogen pressure on the plant. The elevated value of R2 = 0.97 for Mint with RMSE (Root Mean Square Error) < 5 recorded excellent prediction followed by R2 = 0.82 with RMSE < 5-10 for Maxt recorded very good model prediction. Highly significant (P < 0.001) height of Polygonum aviculare was recorded (23.125 ± 0.59) in parasite free plants compared to (20.99 ± 0.96) location-I having Mean ± SD. Both temperature ranges has a significant effect (P < 0.0001) with (F = 5.917; P < 0.0001; F = 25.721; P < 0.0001) three locations; however, the effect of the locations on plants height (P. aviculare) did not differ statistically (F = 2.102; P > 0.05) between two temperature ranges from 25-30 °C and 17-20 °C. According to our findings, plant parasitic powdery mildew (pathogen strain HMLAC226) affected significantly with growth characteristics of prostrate knotweed. [ABSTRACT FROM AUTHOR]

Broomrape (Orobanche cumana Wallr.) is a parasitic weed that causes economic damage in sunflower production in many countries, especially in Central and Eastern Europe, Spain, Turkey, Israel, Iran, Kazakhstan, and China. Genes for resistance to broomrape races A, B, C, D, and E are present in varietal populations of cultivated sunflower. Since broomrape is a highly variable parasitic weed, the breakdown of resistance is a frequent phenomenon, and multiple sources of resistance are needed to control the emerging races. Genes that confer resistance to races F, G, and H and others that have not been assigned a race designation have been identified in wild sunflower species and incorporated into hybrid sunflower through interspecific hybridization. The U.S. Department of Agriculture, Agricultural Research Service, National Plant Germplasm System wild sunflower collection contains 2,239 accessions with 1373 annual accessions represented by 14 species and 866 perennial accessions represented by 39 species. Sunflower germplasm evaluations for resistance to broomrape races have demonstrated that the Helianthus species constitute a substantial reservoir of genes conferring resistance to new virulence broomrape races. The resistance to broomrape, including immunity reported in seven annual and 32 perennial species, provides breeders a broad genetic base from which to search for resistance to existing and newly emerging races. [ABSTRACT FROM AUTHOR]

We first measured the δ13C and δ15N values of root holoparasite Cynomorium songaricum and its hosts from 19 sites across four provinces in northwest China, in an attempt to investigate their nutritional relationship at the Tibetan plateau and the surrounding Gobi desert. Our study showed that the δ13C of C. songaricum closely mirrored the values of its hosts, Nitraria tangutorum and N. sibirica across all sampling sites. C. songaricum was significantly depleted in 13C compared to host plants at the Tibetan plateau, showing an average parasite/host δ13C difference of−0.6 ‰. In contrast, 15N of C. songaricum was significantly enriched by+1.3 ‰ compared to the hosts, implying that these holoparasites had other nitrogen resources. Although no difference in the δ13C and δ15N values between holoparasites and hosts was detected, the δ13C and δ15N values of holoparasites were significantly correlated with those of their hosts at the Gobi desert. The δ13C versus δ15N values were significantly but negatively correlated for the hosts; however, holoparasite/host variation in δ13C was not correlated with the variation in δ15N. The δ13C versus δ15N values were negatively correlated in C. songaricum, and this relationship tended to be magnified along the increasing elevations independent of the host plants. C. songaricum at the Tibetan plateau exhibited different δ13C and δ15N signatures compared with those at the Gobi desert. Furthermore, both δ13C and δ15N values of C. songaricum and its host plants in salt marshes at the Tibetan plateau were different from those in sand sites at the Tibetan plateau and the Gobi desert. Our results indicate that the isotopic difference depends on the different altitudes and habitats and is host-specific. [ABSTRACT FROM PUBLISHER]

The genetic variation among 128 isolates of Monilinia fructicola (Fungi, Ascomycota, Helotiales) from China was analyzed using Inter-Simple Sequence Repeat (ISSR) markers and compared with those of samples from California, USA and New Zealand. A total of 72 reproducible DNA fragments were scored, of which 87.5% (63/72) were polymorphic. The Nei's gene diversity and Shannon's diversity indices of three Chinese regional populations were very similar to that from California. However, several differences were observed among geographic populations of M. fructicola from both within China and between China and California. The analysis of molecular variance (AMOVA) of isolates from different geographic locations suggested that most of the observed genetic variation was found within populations. Results of this study are inconsistent with the hypothesis that the Chinese populations of M. fructicola were derived from a single or few recent migrants from other countries. Instead, our results suggest that M. fructicola has been in China long before its first official recording in 2003. [ABSTRACT FROM AUTHOR]

The roots of Cistanche (C.) tubulosa (Orobanchaceae), a parasitic plant that grows in the Taklamakan desert, are traditionally used as medicines and foods in China. We prepared aqueous ethanol extract (CTE) from the roots of C. tubulosa and its hypocholesterolemic effect was evaluated. Using gene chip and RT-PCR analysis of the livers of mice given CTE (400 mg/kg) for 14 days, we found mRNA expression of molecules related to cholesterol transport [apolipoprotein B and very low density lipoprotein (VLDL) receptor] and metabolism [cytochrome P450 side chain cleave (SCC) and steroid 5α-reductase 2] were up-regulated. The administration of CTE (400 mg/kg) for 14 days significantly suppressed serum cholesterol elevation in high cholesterol diet-fed mice. The mRNA expressions of VLDL receptor and cytochrome P450 SCC were significantly enhanced. In addition, acteoside, a major constituent of CTE, was found to enhance the mRNA expressions of apolipoprotein B, VLDL receptor, and cytochrome P450 SCC in HepG2 hepatocytes. These results suggest that CTE affects the mRNA expressions of molecules related to cholesterol transport and metabolism and exhibits hypocholesterolemic activity in diet-induced hypercholesterolemia mice. Acteoside was involved in the hypocholesterolemic activity of CTE. [ABSTRACT FROM AUTHOR]

Seventeen species of entomophthoralean fungi infecting 15 species of aphids have been reported from mainland China. They belong to seven genera: Batkoa, Conidiobolus, Entomophthora, Neozygites, Pandora, Tarichium and Zoophthora. C. thromboides, E. planchoniana, N. fresenii and P. neoaphidis have the widest distributions covering five regions with the exception of the south-west. Tarichium atrospermum and Z. canadensis were only reported in the eastern region and P. echinospora only in the mid-southern region. Pandora neoaphidis, the most common species, occurred in many aphid populations. Species belonging to the genus Conidiobolus frequently appeared in the warm summer season, however, disease incidence was lower compared to the genus Pandora. [ABSTRACT FROM AUTHOR]

• Concurrent C/N flows between sandalwood and N 2 -fixers are addressed in fields. • C & N from N 2 -fixers to sandalwood via haustoria affect performance of both partners. • Herbaceous plants acquire C & N via transfers from sandalwood and two N 2 -fixers. • Mixed high-value N 2 -fixer/hemiparasite plantation is a sustainable forestry strategy. Root hemiparasites feed on host root xylem and prefer N 2 -fixing hosts. Carbon (C) and nitrogen (N) translocation from hosts to hemiparasites affect growth and development, but detailed C and N economies between hemiparasites and N 2 -fixing hosts are unknown. In a 6-year-old Santalum album (sandalwood) plantation, concurrent movement of C and N between plants over 14 days were traced among N 2 -fixing Acacia confusa , N 2 -fixing Dalbergia odorifera (rosewood) and non-N 2 -fixing hemi-parasitic sandalwood by adding 13C-labeled and 15N-labeled urea to leaves of one species (donor) and tracing the label into other two species (receivers) within three triple-tree combinations. Haustorial connections and host selectivity were also examined on roots and nodules within adjacent plants. N 2 fixation by acacia and rosewood was quantified in the stand by 15N natural abundance. Parasitic haustoria of sandalwood on roots and nodules of N 2 -fixing acacia and rosewood were more frequent than on other non-N 2 -fixing herbaceous plants, indicating strong host selectivity and preference. N 2 fixation supplied 19.7% and 52.3% of the total N in acacia and rosewood, respectively. During 14 days of labeling, more 13C and 15N was transferred from acacia or rosewood to sandalwood than from sandalwood to these two N 2 fixers. Net C and N transfer between tree pairs indicated that hemiparasite sandalwood was the C sink or N sink when associated with N 2 -fixing acacia or rosewood, while N 2 -fixing acacia was the C sink or N sink when associated with N 2 -fixing rosewood. This study indicated that mixed plantations had high rates of interplant nutrient transfer. Our results also showed that the herbaceous plants might acquire some C and N from sandalwood and two N 2 -fixing plants via both direct and indirect transfers, suggesting a nutrient translocation between plants within this community. This mixed plantation of acacia/rosewood/sandalwood could replace low-valued single species or mixed plantations for growing both high-value sandalwood and rosewood heartwoods. Our study quantified nutrient transfer among plants in a sandalwood plantation. These results have improved our understanding of the physiological interactions in resource acquisition between host species and parasitic plants and provided insights into promising mixed-plantation patterns for valuable tropical trees in south China and globally. [ABSTRACT FROM AUTHOR]

Macrosolen plants are parasitic shrubs, several of which are important medicinal plants, that are used as folk medicine in some provinces of China. However, reports on Macrosolen are limited. In this study, the complete chloroplast genome sequences of Macrosolen cochinchinensis, Macrosolen tricolor and Macrosolen bibracteolatus are reported. The chloroplast genomes were sequenced by Illumina HiSeq X. The length of the chloroplast genomes ranged from 129,570 bp (M. cochinchinensis) to 126,621 bp (M. tricolor), with a total of 113 genes, including 35 tRNA, eight rRNA, 68 protein-coding genes, and two pseudogenes (ycf1 and rpl2). The simple sequence repeats are mainly comprised of A/T mononucleotide repeats. Comparative genome analyses of the three species detected the most divergent regions in the non-coding spacers. Phylogenetic analyses using maximum parsimony and maximum likelihood strongly supported the idea that Loranthaceae and Viscaceae are monophyletic clades. The data obtained in this study are beneficial for further investigations of Macrosolen in respect to evolution and molecular identification. [ABSTRACT FROM AUTHOR]

Cistanche deserticola Ma, a perennial parasitic herb of family Orobanchaceae, is mainly parasitic on the roots of the Haloxylon ammodendron Bunge. In view of this special parasitic relationship, we applied random forest (RF) model to forecast potential geographic distribution, and developed a comprehensive habitat suitability model by integrating bioclimatic and soil factors to assess the suitable distribution of C. deserticola and H. ammodendron across China in 2050s and 2070s under RCP2.6, RCP4.5, and RCP8.5, respectively. We modeled the core potential geographic distribution of C. deserticola by overlaying the distribution of these two species, and analyzed the spatial distribution pattern and migration trend of C. deserticola by using the standard deviational ellipse. In addition, we evaluated the accuracy of RF model through three evaluation indexes, and analyzed the dominant climate factors. The results showed that the core potential distribution areas of C. deserticola are distributed in the Xinjiang Uygur Autonomous Region, the junction of Shaanxi–Gansu–Ningxia provinces, and the Inner Mongolia Autonomous Region. The spatial dispersion would intensify with the increasing of emission scenarios, and the geographical habitat is moving towards higher latitude. Among the three evaluation indexes, the area under the ROC curve (AUC) and True Skill Statistic (TSS) have better assessment results. The main bioclimatic factors affecting the distribution are min temperature of coldest month (Bio6), annual precipitation (Bio12), precipitation of wettest month (Bio13), precipitation of wettest quarter (Bio16), and precipitation of warmest quarter (Bio18), among which the importance of precipitation factors is greater than temperature factors. More importantly, the results of this study could provide some guidance for the improvement of desert forest system, the protection of endangered species and the further improvement of the ecological environment. [ABSTRACT FROM AUTHOR]

The article reflects on a report of Pestalotioposis versicolor that cause leaf-trip blight on acacia in China. It states that leaf-tip blight was observed on 80-92 percent of acacia tress in Guangxi, China, causing defoliation and stunting. According to the report, the blight was angular, initiating at the leaf tip and extending to the middle leaf. Diseased leaf tissues became distorted and brown, producing numerous acervuli with black and slimy spore masses. The incident is the first report of the fungus as a pathogen on acacia in China.