Decoupling the molecular regulation of perenniality and flowering in bulbous barley (Hordeum bulbosum)

Global crop production is being challenged by rapid population growth, declining natural resources, and dramatic climatic turnovers. These challenges have prompted plant breeders to explore new ventures to enhance adaptation and sustainability in crops. One intriguing approach to make agriculture more sustainable is by turning annual systems into perennial which offers many economic and biodiversity-friendly benefits. Previous attempts to develop a perennial cereal crop employed a classical breeding approach and extended over a long period with limited success. Thus, elucidating the genetic basis of perenniality at the molecular level can accelerate the breeding process. Here, we investigated the genetic basis of bulb formation in the barley congener species Hordeum bulbosum by elucidating the transcripts presence/absence variation compared with other annual species in the Poaceae, and a differential expression analysis of meristem tissues. The PAV analysis recaptured the expected phylogeny and indicated that H. bulbosum is enriched with developmental and disease responsive genes that are absent among annual species. Next, the abundance of transcripts was quantified and allowed to identify differentially expressed genes that are associated with bulb formation pathways in addition to major circadian clock genes that regulate flowering. A first model for the bulb formation pathway is suggested and include developmental and starch biosynthesis genes. To the best of our knowledge this is the first transcriptome developed for H. bulbosum and the first attempt to describe the regulation of bulb initiation in cereals at the molecular level.

Elazığ İli Karakoçan İlçesi Başyurt Köyü Merasının Botanik Kompozisyonu ile Mera Durumu ve Sağlığının Belirlenmesi

Bu çalışma Elazığ ili Karakoçan ilçesi, Başyurt köyü merasının botanik kompozisyonu ile mera durumu ve sağlığının belirlenmesi amacıyla yürütülmüştür. Mera alanında 15 familyaya ait 41 bitki türünün tespiti yapılmış olup, bitki ile kaplı alan oranı %76.9, botanik kompozisyonda baklagillerin, buğdaygillerin ve diğer familya bitkilerinin oranları sırasıyla %0.9, %35.5 ve %63.6 olarak belirlenmiştir. Merada baskın türlerin Gundelia tournefortii (%19.62), Hordeum bulbosum (%18.28) ve Eremopoa persica (%13.29) olduğu tespit edilmiştir. Mera durumu “zayıf“ olarak belirlenmiştir. Merada bulunan bitkilerin büyük çoğunluğunun istilacı nitelikte olması, botanik kompozisyonda baklagil oranının düşük olması ve mera durumunun zayıf olarak belirlenmesi mera alanının ıslaha ihtiyacı olduğu sonucunu doğurmuştur. Merada münavebeli otlatma sistemine geçilmesi, meranın gübrelenmesi ve mera üzerindeki baskının azaltılması amacıyla meradan yararlanan köy sakinleri, yem bitkileri yetiştiriciliği üretimine teşvik edilmelidir.

LEAVES AREA AND PHOTOSYNTHETIC PIGMENTS OF DOMINANT PLANTS OF RURAL PASTURES IN THE STEPPE BELT OF MOUNT ARAGATS IN ARMENIA

В статье обобщены результаты исследований ассимиляционной поверхности и содержания фотосинтетических пигментов в листьях растений основных луговых групп юго-западного склона горы Арагац (1300-1900 м н.у.м.). Данные территории находятся под сильным воздействием экологических и антропогенных факторов, отличаются низкой продуктивностью, следовательно, нуждаются в коренном улучшении. В рамках настоящей работы была поставлена задача создать базу экспериментальных данных по биологическим параметрам, ответственным за формирование урожая. Объектами исследований были следующие виды злаковых – Коленница (Aegilops cylindrica), Костер (Bromus tectorium), Мятлик (Poa bulbosa), Пырей (Agropyron repens), Ячмень (Hordeum bulbosum), бобовых – Эспарцет (Onobrychis radiata), Клевер (Trifolium pratense), Вика (Vicia variabilis), Люцерна (Medicago sativa) и разнотравных растений – Молочай (Euphorbia virgata), Пижма (Tanacetum vulgare), Скабиоза (Scabiosa bipinnata), Котовник (Nepeta Мussini), Тысячелистник (Achillea millefolium), Полынь (Artemisia absinthium). Площадь листьев определялась весовым методом, экстракция пигментов проводилась с помощью диметилсульфоксида, а измерение их содержания – на спектрофотометре СФ-16. Выявлен широкий диапазон колебаний площади листьев у индивидуальных видов (0,9-11,5), тогда как разница между луговыми группами была незначительной (4,0-5,9 дм2/растение). Сумма пигментов в листьях разнотравных растений на 22 % была меньше, чем у злаковых и бобовых, а соотношение хлорофиллов А и Б колебалось в пределах 1,8-3,5. Таким образом, на исследуемых кормовых угодьях максимальные размеры площади листьев обнаружены у многолетних злаковых, сумма пигментов и хлорофилл А – бобовых, а хлорофилл Б – разнотравных растений. The article summarizes the scientific results on the assimilation surface and the content of photosynthetic pigments in the leaves of plants in the main meadow groups of the southwestern slope of Mount Aragats (1300-1900 m above sea level). Under the strong influence of environmental and anthropogenic factors these territories are characterized by low productivity, therefore, they need efficient improvement. Within the framework of this scientific article, the task was set to create a database of experimental data on biological parameters responsible for the yield farming. The objects of the current research were the following types of cereals – Goatgrass (Aegilops cylindrica), Cheat grass (Bromus tectorium), Bluegrass (Poa bulbosa), Wheatgrass (Agropyron repens), Barley (Hordeum bulbosum), legumes – Sainfoins (Onobrychis radiata), Clover (Trifolium pratenium), Cow vetch (Vicia variabilis), Alfalfa (Medicago sativa), and herbs – Leafy spurge (Euphorbia virgata), Tansy (Tanacetum vulgare), Scabiosa (Scabiosa bipinnata), Catnip (Nepeta Mussini), Yarrow (Achillea milleteminium), Wormwood (Artemisia absinthium). The leaf area was determined by the gravimetric method, pigment extraction was carried out using dimethyl sulfoxide, and their content was measured on an SF-16 spectrophotometer. A wide range of fluctuations in the leaf area in individual species was revealed (0.9-11.5), while the difference between meadow groups was insignificant (4.0-5.9 dm2/plant). The amount of pigments in the leaves of herbs was 22% less than that in cereals and legumes, and the ratio of chlorophylls A and B varied within 1.8-3.5. Thus, on the studied foraging grounds, the maximum leaf area was found in perennial cereals, the sum of pigments and chlorophyll A – in legumes, and chlorophyll B – in herbs. leaves area, photosynthetic pigments, wild plants, natural pastures, steppe belt

High resolution mapping of a Hordeum bulbosum-derived powdery mildew resistance locus in barley using distinct homologous introgression lines

Powdery mildew caused by Blumeria graminis f.sp. hordei (Bgh) is one of the main foliar diseases in barley (Hordeum vulgare L.; Hv). Naturally occurring resistance genes used in barley breeding are a cost effective and environmentally sustainable strategy to minimize the impact of pathogens, however, the primary gene pool of H. vulgare contains limited diversity owing to recent domestication bottlenecks. To ensure durable resistance against this pathogen, more genes are required that could be unraveled by investigation of secondary barley gene-pool. A large set of Hordeum bulbosum (Hb) introgression lines (ILs) harboring a diverse set of desirable resistance traits have been developed and are being routinely used as source of novel diversity in gene mapping studies. Nevertheless, this strategy is often compromised by a lack of recombination between the introgressed fragment and the orthologous chromosome of the barley genome. In this study, we fine-mapped a Hb gene conferring resistance to barley powdery mildew. The initial genotyping of two Hb ILs mapping populations with differently sized 2HS introgressions revealed severely reduced interspecific recombination in the region of the introgressed segment, preventing precise localization of the gene. To overcome this difficulty, we developed an alternative strategy, exploiting intraspecific recombination by crossing two Hv/Hb ILs with collinear Hb introgressions, one of which carries a powdery mildew resistance gene, while the other doesn’t. The intraspecific recombination rate in the Hb-introgressed fragment of 2HS was approximately 20 times higher than it was in the initial simple ILs mapping populations. Using high-throughput genotyping-by-sequencing (GBS), we allocated the resistance gene to a 1.4 Mb interval, based on an estimate using the Hv genome as reference, in populations of only 103 and 146 individuals respectively, similar to what is expected at this locus in barley. The most likely candidate resistance gene within this interval encodes a legume-type lectin-receptor-like protein (LecRLP). Like other LecRLPs that have been implicated in resistance, this gene could be a good candidate for Hb resistance. The reported strategy can be applied as a general strategic approach for identifying genes underlying traits of interest in crop wild relatives.

The Hordeum bulbosum 25S-18S rDNA region: comparison with Hordeum vulgare and other Triticeae

Hordeum vulgare and Hordeum bulbosum are two closely related barley species, which share a common H genome. H. vulgare has two nucleolar organizer regions (NORs), while the NOR of H. bulbosum is only one. We sequenced the 2.5 kb 25S-18S region in the rDNA of H. bulbosum and compared it to the same region in H. vulgare as well as to the other Triticeae. The region includes an intergenic spacer (IGS) with a number of subrepeats, a promoter, and an external transcribed spacer (5′ETS). The IGS of H. bulbosum downstream of 25S rRNA contains two 143-bp repeats and six 128-bp repeats. In contrast, the IGS in H. vulgare contains an array of seven 79-bp repeats and a varying number of 135-bp repeats. The 135-bp repeats in H. vulgare and the 128-bp repeats in H. bulbosum show similarity. Compared to H. vulgare, the 5′ETS of H. bulbosum is shorter. Additionally, the 5′ETS regions in H. bulbosum and H. vulgare diverged faster than in other Triticeae genera. Alignment of the Triticeae promoter sequences suggests that in Hordeum, as in diploid Triticum, transcription starts with guanine and not with adenine as it is in many other plants.