Vegetative propagation of hops (Humulus lupulus L. ): Historical approach and perspectives / Propagação vegetativa do lúpulo (Humulus lupulus L. ): Abordagem histórica e perspectivas

Hop (Humulus lupulus L.) female inflorescences are important raw materials used to produce beers, cosmetics, and medicines. Vegetative propagation is the preferred way of obtaining seedlings for commercial cultivations as female plants produce more lupulin than male plants, a component of commercial interest. It can be carried out by macropropagation (stem cuttings or rhizomes) or micropropagation. This review aimed to systematize different techniques of hop vegetative propagation, with no time frame, from searches in the main academic research bases: Capes Journal Portal, Scielo, Scopus, Web of Science, Science Direct, Google Scholar, and ResearchGate. Most studies are related to micropropagation, mainly addressing different plant regulators and concentrations, as well as types of explants and culture media, strategies to produce virus-free plants, artificial lighting, and cryopreservation. Experiments with stem cuttings are more common regarding macropropagation, but factors such as size and origin of cuttings, rooting period, and the response of different cultivars need to be better evaluated. Cultivation by cuttings allows the production of clones of female plants and micropropagation the production of virus-free clones in a short time and less physical space. Currently, micropropagation has been widely applied to cryopreservation.(AU)

As inflorescências femininas do lúpulo (Humulus lupulus L.) são matérias-primas importantes utilizadas na produção de cervejas, cosméticos e medicamentos. Como as plantas femininas produzem mais lupulina que as masculinas, componente de interesse comercial, a propagação vegetativa é a forma preferencial de obtenção de mudas para os cultivos comerciais. Esta pode ser realizada por macropropagação (estaquia caulinar ou rizomas) ou micropropagação. O objetivo desta revisão foi sistematizar as diferentes técnicas de propagação vegetativa do lúpulo, sem recorte temporal, a partir de buscas nas principais bases de pesquisa acadêmica: Portal de Periódicos Capes, Scielo, Scopus, Web of Science, Science Direct, Google Acadêmico e Research Gate. A maioria dos trabalhos são relacionados à micropropagação, abordando principalmente diferentes reguladores vegetais e concentrações, além de tipos de explantes e meios de cultura, estratégias para produzir plantas livres de vírus, iluminação artificial e criopreservação. Quanto à macropropagação, experimentos com estaquia caulinar são mais comuns, porém fatores precisam ser melhor avaliados tais como tamanho e origem das estacas, período de enraizamento e resposta de diferentes cultivares. O cultivo por estacas permite a produção de clones de plantas femininas e a micropropagação a produção de clones isentos de vírus, em pouco tempo e em menor espaço físico. Atualmente, a micropropagação tem sido muito aplicada à criopreservação.(AU)

The BOP-type co-transcriptional regulator NODULE ROOT1 promotes stem secondary growth of the tropical Cannabaceae tree Parasponia andersonii.

Tree stems undergo a massive secondary growth in which secondary xylem and phloem tissues arise from the vascular cambium. Vascular cambium activity is driven by endogenous developmental signalling cues and environmental stimuli. Current knowledge regarding the genetic regulation of cambium activity and secondary growth is still far from complete. The tropical Cannabaceae tree Parasponia andersonii is a non-legume research model of nitrogen-fixing root nodulation. Parasponia andersonii can be transformed efficiently, making it amenable for CRISPR-Cas9-mediated reverse genetics. We considered whether P. andersonii also could be used as a complementary research system to investigate tree-related traits, including secondary growth. We established a developmental map of stem secondary growth in P. andersonii plantlets. Subsequently, we showed that the expression of the co-transcriptional regulator PanNODULE ROOT1 (PanNOOT1) is essential for controlling this process. PanNOOT1 is orthologous to Arabidopsis thaliana BLADE-ON-PETIOLE1 (AtBOP1) and AtBOP2, which are involved in the meristem-to-organ-boundary maintenance. Moreover, in species forming nitrogen-fixing root nodules, NOOT1 is known to function as a key nodule identity gene. Parasponia andersonii CRISPR-Cas9 loss-of-function Pannoot1 mutants are altered in the development of the xylem and phloem tissues without apparent disturbance of the cambium organization and size. Transcriptomic analysis showed that the expression of key secondary growth-related genes is significantly down-regulated in Pannoot1 mutants. This allows us to conclude that PanNOOT1 positively contributes to the regulation of stem secondary growth. Our work also demonstrates that P. andersonii can serve as a tree research system.

Transforming, Genome Editing and Phenotyping the Nitrogen-fixing Tropical Cannabaceae Tree Parasponia andersonii.

Parasponia andersonii is a fast-growing tropical tree that belongs to the Cannabis family (Cannabaceae). Together with 4 additional species, it forms the only known non-legume lineage able to establish a nitrogen-fixing nodule symbiosis with rhizobium. Comparative studies between legumes and P. andersonii could provide valuable insight into the genetic networks underlying root nodule formation. To facilitate comparative studies, we recently sequenced the P. andersonii genome and established Agrobacterium tumefaciens-mediated stable transformation and CRISPR/Cas9-based genome editing. Here, we provide a detailed description of the transformation and genome editing procedures developed for P. andersonii. In addition, we describe procedures for the seed germination and characterization of symbiotic phenotypes. Using this protocol, stable transgenic mutant lines can be generated in a period of 2-3 months. Vegetative in vitro propagation of T0 transgenic lines allows phenotyping experiments to be initiated at 4 months after A. tumefaciens co-cultivation. Therefore, this protocol takes only marginally longer than the transient Agrobacterium rhizogenes-based root transformation method available for P. andersonii, though offers several clear advantages. Together, the procedures described here permit P. andersonii to be used as a research model for studies aimed at understanding symbiotic associations as well as potentially other aspects of the biology of this tropical tree.

A new Shivaphis species (Hemiptera: Aphididae) on the Chinese endemic plant, Pteroceltis tatarinowii.

A new species of aphid in subfamily Calaphidinae, Shivaphis pteroceltis sp. n., is described from China. This aphid feeds on Pteroceltis tatarinowii, an endemic tree commonly planted as an ornamental in China and used in the production of Xuan paper. The life cycle is described, and the descriptions of fundatrices, apterous and alate viviparae, oviparae and males are provided. COI sequences have been deposited in Genbank, and the type specimens are deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing and Forestry Bureau of Central District, Zaozhuang City, Shandong Province, China.

Responses of two invasive plants under various microclimate conditions in the Seoul metropolitan region.

The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO(2) concentrations differed significantly between the urban (14.8 °C and 439 ppm CO(2)) and suburban (13.0 °C and 427 ppm CO(2)) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas.