Cost-effectiveness analysis of subsidy schemes for industrial timber development and carbon sequestration in Japanese forest plantations

This study uses simulations to investigate the effects of implementing two different Japanese forestry subsidy systems on timber production and carbon stock, and examines the consequences for harvesting strategies. An existing Local Yield Table Construction System (LYCS), a wood conversion algorithm, and a harvesting cost model were used in the simulations to test the applicability of different subsidies to the thinning of stands. Using forest inventory data collected by local government staff, simulation output was used to calculate forestry profits, carbon stocks, subsidies, the amount of labor required, and the cost effectiveness of investing in subsidies. By comparing the output of simulations based on two scenarios, we found that both the clear-cutting area and the amount of harvested timber were larger under Scenario 2, in which the rules governing subsidy allocations are more relaxed, than under Scenario 1, in which the rules are more restrictive. Because the harvested timber under Scenario 1 was mainly produced by clear-cutting, the forestry profits and the subsidy predicted in the early period of the simulation, were larger under Scenario 1 than under Scenario 2. In contrast, the carbon stock was larger under Scenario 2 than under Scenario 1. The simulation model is likely to be useful for improving Plan-Do-Check-Act cyclesimplemented in Japanese forest management systems.     

Genetic diversity and spatial distribution of rhizobial bacteria nodulating on black locust (Robinia pseudoacacia) rhizospheres

Black locust (Robinia pseudoacacia L.) is an economically and ecologically important tree in Japan. The species is widely used for afforestation because of its symbiotic relationship with nitrogen-fixing rhizobia. In this study, genetic diversity of rhizobia isolated from black locust nodules and spatial distribution of their genotypes were examined. From a coastal forest, six black locust saplings including the whole root systems were collected and positions of nodules on the roots were recorded. Bacteria were isolated from each nodule and then genotyped by Polymerase Chain Reaction (PCR)-Restriction Fragment Length Polymorphism (RFLP) and sequencing analysis of the 16S rRNA gene. Dendrogram analysis based on PCR-RFLP and sequencing analysis indicated that Mesorhizobium species dominantly colonized black locust roots in this forest, occupying at least 77% of living nodules. Positions and PCR-RFLP genotypes of the nodules revealed that rhizobia isolated from neighbouring nodules tended to have the same genotype in some cases. Statistical analysis has supported this fact. The clustering distribution of nodules in the same RFLP groups should be considered to contribute to the large genetic diversity of rhizobia.     

<Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>-mediated transformation for random insertional mutagenesis in <Emphasis Type="Italic">Colletotrichum lagenarium</Emphasis>

Random insertional mutagenesis using a marker DNA fragment is an effective method for identifying fungal genes relevant to morphogenesis, metabolism, and so on. Agrobacterium tumefaciens-mediated transformation (AtMT) has long been used as a tool for the genetic modification of a wide range of plant species. Recent study has indicated that A. tumefaciens could transfer T-DNA not only to plant cells but also to fungal cells. In this study, AtMT was applied to Colletotrichum lagenarium for random insertional mutagenesis. We constructed a binary vector pBIG2RHPH2 carrying a hygromycin-resistant gene cassette between the right and left borders of T-DNA. Optimal co-cultivation of C. lagenarium wild-type 104-T with pBIG2RHPH2-introduced A. tumefaciens C58C1 led to the production of 150–300 hygromycin-resistant transformants per 10⁶ conidia. Southern blot analysis revealed that T-DNA was mainly integrated at a single site in the genome and at different sites in transformants. The T-DNA inserts showed small truncations of either end, but the hygromycin-resistant gene cassette inside the T-DNA was generally intact. The mode of T-DNA insertion described above resulted in highly efficient gene recovery from the transformants by thermal asymmetrical interlaced-polymerase chain reaction. The fungal genomic DNA segments flanking T-DNA were identified from five of eight mutants that had defective melanin biosynthesis. The sequence from one of the segments was identical to that of the melanin biosynthesis gene PKS1 of C. lagenarium, which we previously characterized. These results strongly support our notion that AtMT is a possible tool for tagging genes relevant to pathogenicity in the plant pathogenic fungus C. lagenarium.     

Platelet dysfunction in Chediak-Higashi syndrome-affected cattle

A serious symptom of cattle affected with Chediak-Higashi syndrome (CHS) is a bleeding tendency. This diathesis is characterized by insufficient platelet aggregation as a result of depressed response to collagen. One possible cause for the depression is a decrease in contribution of endogenous agonists such as ADP or thromboxane A(2), which are released following collagen stimulation. However, these endogenous agonists play only a minor role in collagen-induced aggregation of bovine platelets. More importantly, activation of phospholipase C as a result of a direct action of collagen is depressed, leading to a depression of Ca(2+) mobilization, in platelets from CHS-affected cattle. Several types of collagen receptor are proposed to work in concert to induce aggregation. Among them, glycoprotein VI (GPVI) and GPIa/IIa (integrin alpha2 beta1) have been supposed to play dominant roles in collagen-induced aggregation. However, there are arguments about the role of each receptor, especially the role of GPIa/IIa, and the crosstalk between receptors. Recently, we reported that the Ca(2+) signaling produced by rhodocytin, which had been first reported to be an agonist for the collagen receptor GPIa/IIa, produced much less Ca(2+) signaling in CHS platelets than in normal ones, whereas that produced by GPVI activators was normal. These suggest that GPIa/IIa or the rhodocytin-associated pathway is impaired in CHS platelets. CHS platelets are valuable to reassess the mechanism of collagen-dependent signal transduction system and to delineate the inter-relationship among collagen receptors.     

Cloning and characterization of pea apyrases: involvement of <Emphasis Type="Italic">PsAPY1 </Emphasis>in response to signal molecules from the pea pathogen <Emphasis Type="Italic">Mycosphaerella pinodes</Emphasis>

 Two nucleoside triphosphatase (NTPase) cDNA clones were isolated from a cDNA library of Pisum sativum L., cv. Midoriusui. The genes encoding the cDNAs were designated PsAPY1 and PsAPY2. PsAPY1 included the N-terminal amino acid sequence of an NTPase bound to pea cell wall. The phylogenic analysis indicated that PsAPY1 belongs to an NTPase subfamily responsive to environmental stimuli and that PsAPY2 belongs to a discrete subfamily, the physiological role of which is almost unknown. The adenosine triphosphatase activity of recombinant PsAPY1 was regulated by an elicitor and a suppressor from the pea pathogen Mycosphaerella pinodes. Based on these findings, we discuss the role of NTPases in response to biological stresses. Received: May 27, 2002 / Accepted: July 31, 2002     

Flagellin from Pseudomonas syringae pv. tabaci induced hrp-independent HR in tomato

We have previously shown that flagellin of Pseudomonas syringae pv. tabaci is an elicitor that induces a hypersensitive reaction (HR) in nonhost tomato cells. Flagellin is the major HR elicitor produced by this pathogen, as shown by the inability of a flagellin-defective mutant, ΔfliC, to induce HR. Also, a ΔfliD mutant that secretes large amounts of monomer flagellins induces a strong HR in tomato. In this study, the possible involvement of an Hrp type III secretion system (TTSS) in flagellin-induced HR was investigated using flagella-defective mutants or Hrp TTSS-defective mutants. The hrcC gene encodes HrcC protein, which is required for Hrp pilus formation in the outer membrane. An hrcC mutation, introduced into the wild-type, ΔfliC, and ΔfliD mutants of P. syringae pv. tabaci did not affect swimming motility or flagellin secretion, whereas all ΔhrcC, ΔfliC, and ΔfliD mutants lost the ability to cause disease on host tobacco leaves. However, the ΔhrcC mutant and the ΔfliD/ΔhrcC double mutant were still able to induce HR cell death, expression of one of the defense-related genes hsr203J, and the generation of hydrogen peroxide in nonhost tomato cells. Thus, flagellin is required for both pathogenicity in host tobacco and HR in nonhost tomato. On the other hand, hrp TTSS is necessary for pathogenicity on host tobacco but is not indispensable to induce HR in nonhost tomato. These results clearly show that flagellin-induced HR is hrp-independent in tomato.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB049570     

Defense responses of Arabidopsis thaliana inoculated with Pseudomonas syringae pv. tabaci wild type and defective mutants for flagellin (ΔfliC) and flagellin-glycosylation (Δorf1)

Flagellin, an essential component of the bacterial flagellar filament, is capable of inducing a hypersensitive response (HR), including cell death, in a nonhost plant. A flagellin-defective mutant (ΔfliC) of Pseudomonas syringae pv. tabaci lacks both the flagellar filament and motility, whereas a flagellin-glycosylation-defective mutant (Δorf1) retains the flagellar filament but lacks the glycosyl modification of flagellin protein. To investigate the role of flagellin protein and its glycosylation in the interaction with its nonhost Arabidopsis thaliana, we analyzed plant responses after inoculation with these bacteria. Inoculation with wild-type P. syringae pv. tabaci induced HR, with the generation of reactive oxygen species and cell death. In contrast, inoculation with either ΔfliC or Δorf1 mutant induced a low level of HR, and inoculated leaves developed a disease-like yellowing. These mutant bacteria multiplied better than the wild-type bacteria in A. thaliana. These results indicate that A. thaliana expresses a defense reaction in response to the bacterial flagellin with its glycosyl structure.