Diversity of powdery mildew fungi from protected areas of Jizzak region, Uzbekistan - a checklist

and melons: diversity, monitoring, and creation of an electronic database”. Valuable suggestions of anonymous reviewers for improving the manuscript are appreciated.


INTRODUCTION
Powdery mildews belong to the Erysiphaceae.The main geographical regions of the distribution are in the temperate zone of the northern hemisphere.They are obligate biotrophs responsible for diseases in many plants.They are cosmopolitan, widespread on various hosts including vegetables, trees, herbs, shrubs, grasses, ornamental plants and weeds (Braun 1987).In many cases, powdery mildew fungi are more common in cultivated plant hosts (Pawar & Patil 2011).The fungi infect almost every group of plants, i.e., from grasses to higher angiosperms (Braun & Cook 2012).Powdery mildews are easily visible on infected plant leaves, stems, and fruits.The first symptoms appear as white powdery spots on leaves, branches and sometimes on fruits.Over time, disease severity increases under favorable conditions.Disease symptoms usually appear with the onset of summer and begin to disappear during the scorching heat and rainy season (Pap et al. 2013).
Recently, invasive species of powdery mildew, originating from other regions of the world, have spread extensively in Uzbekistan (e.g., Erysiphe australiana on Lagerstroema indica); they are mostly found on introduced trees and shrubs that are widely used for landscaping (Nabieva et al. 2021).
The current study aims to compile a checklist of powdery mildew of vascular plants of the Nuratau Nature Reserve, Zaamin Nature Reserve, and Zaamin National Nature Park in the Jizzakh region.The present checklist serves as one of the sources to make the complete modern list of powdery mildew of the Rebuplic of Uzbekistan.

METHODS
About 1,000 powdery mildew fungi were collected in 2009-2022 years in different habitats of protected natural areas.Samples were collected from the affected parts of the plants and either used fresh or stored dry as herbarium material until analysis, as described by Heluta (1989).These are designated in the checklist by the following abbreviations: NNR -Nuratau Nature Reserve, ZNR -Zaamin Nature Reserve, ZNNP -Zaamin National Nature Park.Specimens: Chasmothecia, conidiophores, and conidia were observed and measured in oil immersion, using a Moticam 5N-300M microscope at a magnification up to ×400 and identified using the relevant literature (Zaprometov 1926;1928;Golovin 1941;Gaponenko 1965;Panfilova & Gaponenko 1983;Gaponenko et al. 1983;Heluta et al. 2004;Braun 2012;Raximova et al. 2014Raximova et al. ). (1968Raximova et al. -1993) ) and 'Flora of Uzbekistan ' (1941-1962).All collected specimens are stored in the Fungarium of the Institute of Botany in Tashkent.Voucher specimens for each species of powdery mildew fungi are cited in the checklist below.The name of the collector is designated by abbreviation: IM -Ilyor Mustafaev, IOZ -Islom Ortiqov, XD -Xo`jaqulova Durdona.The taxonomy and nomenclature of powdery mildew fungi in the checklist follow international databases Index Fungorum (2023) and Mycobank (2023).The nomenclature of host plants is given according to powo.science.kew.org/results(2023).All collected specimens are stored in the Tashkent Mycological Herbarium (TASM) of the Institute of Botany.

RESULTS
In the protected areas of the Jizzakh region, including NNR, ZNR, and ZNNP, an extensive survey uncovered a diverse range of powdery mildew fungi.These findings encompass nine genera and 57 species, with 69 forms and four varieties, all identified through morphological characteristics.These fungi were documented on 137 host plant species, further grouped into 107 genera and 34 families (Table 1).Erysiphe emerged as the most species-rich genus, boasting 19 species, 26 forms, and four variations, closely followed by Leveillula with 16 species and 27 forms.Podosphaera accounted for nine species and three forms, while Phyllactinia exhibited four species and four forms.Additionally, Golovinomyces and Sphaerotheca each comprised four and three species, respectively, while Uncinula, Neoerysiphe, and Blumeria were each confined to one host plant species.
Erysiphe species demonstrated the broadest host range, infecting 57 host plant species (41.6 % of the total), followed by Leveillula with 35 host plant species (25.4 %), and Podosphaera with 19 host plant species (13.8 %).Sphaerotheca was found on 11 host plant species (8.0 %), while the remaining genera-Blumeria, Phyllactinia, Golovinomyces, Neoerysiphe, and Uncinula-showed isolation to fewer host species.This comprehensive investigation highlights the wide distribution of powdery mildew fungi in the protected areas of the Jizzakh region, underscoring the need for further research to uncover their ecological roles and potential impacts.
Among them, Helichrysum nuratavicum, Phlomis nubilans are endemic species for Nuratau ridge and Phlomis nubilans, Helichrysum nuratavicum and Platanus orientalis are listed in the Red Data Book of Uzbekistan (2019).

DISCUSSION
It is known that the diversity of the powdery mildew fungi is closely related to the diversity of the plant flora.Uzbekistan's plant flora consists of more than 4,500 species and 88 species (334 forms) of powdery mildew fungi were registered on 778 host plant species (Gaponenko et al. 1983).The plant flora from protected areas of the Jizzakh region includes 1986 species of 645 genera and 115 families (Tojibaev et al. 2015) and found 57 species, 69 forms and 4 variaties of powdery mildew on 137 host plant species from 34 families.
The distribution of powdery mildew species in host plants is given based on the regions of Jizzakh region in which they are distributed.The largest number of powdery mildew and host plants were found in the Nuratau Nature Reserve (8 genera, 40 species, 41 forms, 3 forms, of the total species number 70.17%), followed by the Zaamin National Nature Park (7 genera, 35 species, 32 forms, 3 varieties, of the total species number 61.40%), Zaamin Nature Reserve (8 genera, 20 species, 36 forms, 2 varieties, of the total species number 35.08 %).
It is noted that studies on powdery mildew fungi of many regions of Uzbekistan including the Anger river basin, and Fergana valley carried out by some mycologists (Panfilova & Gaponenko 1963;Gaponenko et al. 1983;Abdurazakov et al. 2021).The diversity of powdery mildew fungi in protected areas of the Jizzakh region has been compared with their research results (Table 2).
This diversity of powdery mildew fungi of protected areas of the Jizzakh region is represented by 9 genera and 57 species, 69 forms and 4 variaties species and has approximately 30.80% of the currently known mildew fungi biota of Uzbekistan.On the territory of protected areas of the Jizzakh region, the powdery mildew diseases occur frequently and severely damage plants belonging to Aegilops, Alhagi, Artemisia, Alyssum, Capparis, Cousinia, Convolvulus, Ferula, Morus, Populus, Rosa, Rumex, and Trifolium.The present checklist is the third work about powdery mildew microfungi of Uzbekistan and serves as one of the sources for a complete list of powdery mildew microfungi of the Rebuplic of Uzbekistan.

Figure 1 .
Figure 1.The map illustrates the location of the protected areas in the Jizzakh region.

Table 1 . In this section, the scientific name of host plants along with the powdery mildew fungi occurring on them are provided. Host plant (scientific name ) Powdery mildew fungi (scientific name)
Urtica dioica, Vitis vinifera,  Ziziphora tenuior etc.This work represents itself as a checklist of powdery mildew fungi in the Jizzakh region of protected areas.The fungal species listed below have been arranged in alphabetical order.