Hao Hu

• PhD
• PostDoc Position at University of California, Riverside

Aphids are pests of chrysanthemum that employ plant volatiles to select host plants and ingest cell contents to probe host quality before engaging in prolonged feeding and reproduction. Changes in volatile and non-volatile metabolite profiles can disrupt aphid-plant interactions and provide new methods of pest control. Chrysanthemol synthase (CHS)...

E)‐β‐Farnesene (EβF) is the predominant constituent of the alarm pheromone of most aphid pest species. Moreover, natural enemies of aphids use EβF to locate their aphid prey. Some plant species emit EβF, potentially as a defense against aphids, but field demonstrations are lacking. Here, we present field and laboratory studies of flower defense sho...

Significance The m ⁷ G cap is the canonical RNA cap in eukaryotes, but other noncanonical RNA caps exist, including the NAD ⁺ cap. NAD captureSeq has been widely used to profile NAD ⁺ -capped RNAs (NAD-RNAs) in prokaryotes and eukaryotes. However, NAD captureSeq reacts at a low level with m ⁷ G-RNAs and introduces copper ions that cause RNA fragmen...

The modification of RNA species has been well documented for decades. In mRNA, both internal and 5′ end modifications can occur. Specifically, modification of the 5′ end is known as capping. The 5′-5′ triphosphate linked N7-methyl guanosine (m⁷G) structure is involved in a myriad of RNA processes and was long presumed to be the only functional cap....

Pyrethrins constitute a class of terpene derivatives with high insecticidal activity and are mainly synthesized in the capitula of the horticulturally important plant, Tanacetum cinerariifolium. Treatment of T. cinerariifolium with methyl jasmonate (MeJA) in the field induces pyrethrin biosynthesis, but the mechanism linking MeJA with pyrethrin bio...

Photosynthesis requires chloroplasts, in which most proteins are nucleus-encoded and produced via cytoplasmic translation. The translation initiation factor eIF5B gates the transition from initiation (I) to elongation (E), and the Kozak motif is associated with translation efficiency, but their relationship is previously unknown. Here, with ribosom...

Recent studies show that nocturnal pollinators may be more important to ecosystem function and food production than is currently appreciated. Here, we describe an agricultural field study of pyrethrum (Tanacetum cinerariifolium) flower pollination. Pyrethrum is genetically self‐incompatible and thus is reliant on pollinators for seed set. Our polli...

Pyrethrum (Tanacetum cinerariifolium), a perennial herb within the Tanacetum genus, stands as a crucial source of natural insecticides pyrethrins which have been utilized for centuries. This study delves into the historical utilization of pyrethrum and elucidates the biosynthetic pathways of pyrethrum, uncovering the majority of genes responsible f...

(E)-β-Farnesene (EBF) serves as the primary component of the alarm pheromone used by most aphid pest species. Pyrethrum (Tanacetum cinerariifolium) exhibits tissue-specific regulation of EBF accumulation and release, effectively mimicking the aphid alarm signal, deterring aphid attacks while attracting aphid predators. However, cultivated chrysanth...

The occurrence of NAD⁺ as a non-canonical RNA cap has been demonstrated in diverse organisms. TIR domain-containing proteins present in all kingdoms of life act in defense responses and can have NADase activity that hydrolyzes NAD⁺. Here, we show that TIR domain-containing proteins from several bacterial and one archaeal species can remove the NAM...

Main conclusion In flowers multiple secretory systems cooperate to deliver specialized metabolites to support specific roles in defence and pollination. The collective roles of cell types, enzymes, and transporters are discussed. Abstract The interplay between reproductive strategies and defense mechanisms in flowering plants has long been recogni...

Natural pyrethrins have high application value, and are widely used as a green pesticide in crop pest prevention and control. Pyrethrins are mainly extracted from the flower heads of Tanacetum cinerariifolium; however, the natural content is low. Therefore, it is essential to understand the regulatory mechanisms underlying the synthesis of pyrethri...

Ribosome biogenesis is essential for protein synthesis in gene expression. Yeast eIF5B has been shown biochemically to facilitate 18S ribosomal RNA (rRNA) 3' end maturation during late-stage 40S ribosomal subunit assembly and gate the transition from translation initiation to elongation. But the genome-wide effects of eIF5B have not been studied at...

Pyrethrins, synthesized in the perennial plant Tanacetum cinerariifolium, are a class of terpene mixtures with high insecticidal activity and low human toxicity, which are widely used in plant-derived pesticides. Numerous studies have identified multiple pyrethrins biosynthesis enzymes, which can be enhanced by exogenous hormones such as methyl jas...

Pyrethrum (Tanacetum cinerariifolium) is one of the most important industrial crops for the extraction of pyrethrins, which are natural insecticidal compounds. Progress in pyrethrum molecular breeding with the objective of increasing pyrethrin content has been slow for lack of a suitable gene transfer system. Regeneration recalcitrance is a crucial...

Background Traditional CRISPR/Cas9 systems that rely on U6 or U3 snRNA promoters (RNA polymerase III-dependent promoters) can only achieve constitutive gene editing in plants, hampering the functional analysis of specifically expressed genes. Ribozyme-mediated CRISPR/Cas9 systems increase the types of promoters which can be used to transcribe sgRNA...

Natural pyrethrins have been widely used as natural pesticides due to their low mammalian toxicity and environmental friendliness. Previous studies have mainly focused on Tanacetum cinerariifolium, which contains high levels of pyrethrins and volatile terpenes that play significant roles in plant defense and pollination. However, there is little in...

Plant defensive mimicry based on the aphid alarm pheromone (E)-β-farnesene (EβF) was previously shown to operate in Tanacetum cinerariifolium (Asteraceae) flowers. Germacrene D (GD), is another dominant volatile of T. cinerariifolium flowers and may modulate both defense and pollination. Here, we find that the increase in GD/EβF ratio at later deve...

Significance Some RNAs in both prokaryotes and eukaryotes were recently found to contain the NAD ⁺ cap, indicating a novel mechanism in gene regulation through noncanonical RNA capping. Copper-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry has been used to label NAD ⁺ -capped RNAs (NAD-RNAs) for their identification. However, copper-c...

p>The secondary metabolite composition and relative abundance in leaves and ovaries of the Chrysanthemum morifolium model cultivar '1581' were analyzed by SPME extraction and GC-MS analysis. The terpenoids represented the dominant group of volatiles. Based on conserved sequences FDS-like genes identified in a transcriptome database derived from chr...

Table S1 Volatile metabolites with a >5‐fold intensity change between transgenic lines and wild type plants. Table S2 Non‐volatile metabolites with a >5‐fold intensity difference between transgenic lines and wild type plants. Table S3 NMR data for chrysanthemyl‐6‐O‐malonyl‐β‐D‐glucopyranoside in acetonitrile D3 (300 K). Figure S1 GC‐MS chromatog...

Natural pyrethrins accumulate to high concentrations in the flower achenes of pyrethrum (Tanacetum cinerariifolium). They are extracted from dried flowers and widely used as a natural pesticide. Chrysanthemol synthase (CHS) is the first key enzyme in the biosynthesis of pyrethrins. In this work, a 1128 bp TcCHS promoter fragment was cloned from pyr...

Chrysanthemyl diphosphate synthase (CDS) is the first pathway-specific enzyme in the biosynthesis of pyrethrins, the most widely used plant-derived pesticide. CDS catalyzes c1′-2-3 cyclopropanation reactions of two molecules of dimethylallyl diphosphate (DMAPP) to yield chrysanthemyl diphosphate (CPP). Three proteins are known to catalyze this cycl...

Florist-s chrysanthemum is one of the most important flower crops in the global floricultural industry today. The susceptibility of many cultivars to a variety of pests, especially aphids, causes large economic loss. In this study, 29 chrysanthemum cultivars in our germplasm were evaluated on the susceptibility to aphids in the field. The cultivars...