Early Diagnosis of Pine Wilt Disease in Pinus thunbergii Based on Chlorophyll Fluorescence Parameters

Abstract

As the most severe forestry quarantine disease in several countries, pine wilt disease (PWD) causes substantial economic losses and poses a significant threat to the forest ecosystem. It is necessary to find a rapid and sensitive method for the early diagnosis of the disease to control the development of the disease effectively. This paper investigated the effect of Bursaphelenchus xylophilus（the pinewood nematode; PWN）on the chlorophyll fluorescence kinetic curve (OJIP curve) and the parameters of needles using four-year-old Pinus thunbergii as experimental materials and chlorophyll fluorescence analysis as a technical tool. It was shown by the results in the OJIP curve that the fluorescence intensity of the inoculated plants was significantly increased at points O and I. Additionally, the relative variable fluorescence intensity at points K and J was comparable to that of the control plants. Several chlorophyll fluorescence parameters of the treatment significantly increased or decreased with disease progression. At the same time, the control group had no significant changes in each parameter. Therefore, chlorophyll fluorescence parameters can be used as indicators for the early diagnosis of PWD, among which the DIo/RC parameter was the best. In summary, PWN invasion will produce fluorescence on the PSII of P. thunbergii, and its chlorophyll fluorescence parameters are expected to achieve early PWD diagnosis.

Efficacy of chlorophyll a fluorescence kinetics and JIP test for early detection of leaf-gall disease in Cordia dichotoma

“…of active PS-II RCs (Joly et al, 2005;Eullaffroy et al, 2009;Panda & Sarkar, 2012). Ficus religiosa leaves with gall infestation also yielded comparable results (Bhatt et al, 2022d;Liu et al, 2023). With the penetration of infection, the antenna size of infested leaves enlarged and attempted to absorb more energy, so the ABS/RC and TR/RC increased with the disease manifested in the leaves (Table 1).…”

“…But the gall formation alters biochemical and biophysical responses which negatively affect plant growth and development. When the disease spreads, leaves start to dry up and shrink, which is an obvious sign of damage in photosynthetic machinery and chlorophyll degradation (Bhatt et al, 2022d;Bhatt & Soni, 2023;Liu et al, 2023). Chlorophyll fluorescence kinetics is an aid as an advanced fast, sensitive, and non-destructive tool for analyzing the photosynthetic performance of leaves of the stressed.…”

Response analysis of Pinus sibirica to pine wood nematode infection through transcriptomics and metabolomics study

“…The results were consistent with previous studies. Some researchers observed a significant decrease in net light and rate, chlorophyll content, and stomatal conductance following PWN infection in pine trees, indicating that PWN may cause damage to the photosynthetic structure of pine needles ( Liu et al., 2023 ). In this study, a large number of down-regulated genes were enriched in photosynthesis (ko00195), photosynthesis-antenna proteins (ko00196) and carotenoid biosynthesis (ko00906) with high rich factors ( Figure 3C ), indicating that photosynthesis continued to be inhibited in P. sibirica seedlings after PWN inoculation.…”

Chlorophyll a Fluorescence: A Method of Biotic Stress Detection

“…In another study, the use of OJIP-test showed that DIo/RC parameter is the best indicator for the diagnosis of Bursaphelenchus xylophilus that is a pinewood nematode (PWN) of Pinus thunbergia [85], suggesting that this method may assist in disease detection localized in other plant organs, such as roots. In other interaction, it was demonstrated that F v /F 0 , F 0 , F m , and ABS/RC parameters were useful for identifying the physiological changes produced by F. verticillioides infection in maize plants [86].…”